diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/ActivityWork.java b/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/ActivityWork.java
index 13a4300fc..0ead19ab8 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/ActivityWork.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/ActivityWork.java
@@ -1,6 +1,6 @@
 package org.navalplanner.business.workorders.entities;
 
-import org.hibernate.validator.NotNull;
+import java.math.BigDecimal;
 
 public class ActivityWork {
 
@@ -10,9 +10,16 @@ public class ActivityWork {
         return id;
     }
 
-    @NotNull
     private Integer workingHours;
 
+    private BigDecimal percentage;
+
+    public enum HoursPolicies {
+        NO_FIXED, FIXED_HOURS, FIXED_PERCENTAGE
+    };
+
+    private HoursPolicies hoursPolicy = HoursPolicies.NO_FIXED;
+
     public void setWorkingHours(Integer workingHours) {
         this.workingHours = workingHours;
     }
@@ -21,4 +28,20 @@ public class ActivityWork {
         return workingHours;
     }
 
+    public void setPercentage(BigDecimal percentage) {
+        this.percentage = percentage;
+    }
+
+    public BigDecimal getPercentage() {
+        return percentage;
+    }
+
+    public void setHoursPolicy(HoursPolicies hoursPolicy) {
+        this.hoursPolicy = hoursPolicy;
+    }
+
+    public HoursPolicies getHoursPolicy() {
+        return hoursPolicy;
+    }
+
 }
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/TaskWork.java b/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/TaskWork.java
index 5587022ae..dc3707c89 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/TaskWork.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/TaskWork.java
@@ -1,10 +1,7 @@
 package org.navalplanner.business.workorders.entities;
 
-import java.util.ArrayList;
 import java.util.Date;
-import java.util.HashSet;
 import java.util.List;
-import java.util.Set;
 
 import org.hibernate.validator.NotNull;
 
@@ -18,21 +15,15 @@ public abstract class TaskWork {
 
     private Date endDate;
 
-    private Set<ActivityWork> activityWorks = new HashSet<ActivityWork>();
+    private Boolean mandatoryInit = false;
+
+    private Boolean mandatoryEnd = false;
+
+    private String description;
 
     public abstract Integer getWorkHours();
 
-    public void setActivities(List<ActivityWork> activities) {
-        this.activityWorks = new HashSet<ActivityWork>(activities);
-    }
-
-    public void addActivity(ActivityWork activityWork) {
-        activityWorks.add(activityWork);
-    }
-
-    public List<ActivityWork> getActivities() {
-        return new ArrayList<ActivityWork>(activityWorks);
-    }
+    public abstract List<ActivityWork> getActivities();
 
     public long getId() {
         return id;
@@ -73,15 +64,32 @@ public abstract class TaskWork {
         this.endDate = endDate;
     }
 
-    public abstract void remove(TaskWork lastAsTask);
+    public void setMandatoryInit(Boolean mandatoryInit) {
+        this.mandatoryInit = mandatoryInit;
+    }
 
-    public abstract void replace(TaskWork old, TaskWork newTask);
+    public Boolean isMandatoryInit() {
+        return mandatoryInit;
+    }
+
+    public void setMandatoryEnd(Boolean mandatoryEnd) {
+        this.mandatoryEnd = mandatoryEnd;
+    }
+
+    public Boolean isMandatoryEnd() {
+        return mandatoryEnd;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+
+    public String getDescription() {
+        return description;
+    }
 
     public abstract TaskWorkContainer asContainer();
 
-    public void forceLoadActivities() {
-        for (ActivityWork activityWork : activityWorks) {
-            activityWork.getWorkingHours();
-        }
-    }
+    public abstract void forceLoadActivities();
+
 }
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/TaskWorkContainer.java b/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/TaskWorkContainer.java
index 4ad08da91..c0c8abbc5 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/TaskWorkContainer.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/TaskWorkContainer.java
@@ -66,4 +66,20 @@ public class TaskWorkContainer extends TaskWork implements ITaskWorkContainer {
         return result;
     }
 
+    @Override
+    public void forceLoadActivities() {
+        for (TaskWork taskWork : children) {
+            taskWork.forceLoadActivities();
+        }
+    }
+
+    @Override
+    public List<ActivityWork> getActivities() {
+        List<ActivityWork> activities = new ArrayList<ActivityWork>();
+        for (TaskWork taskWork : children) {
+            activities.addAll(taskWork.getActivities());
+        }
+        return activities;
+    }
+
 }
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/TaskWorkLeaf.java b/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/TaskWorkLeaf.java
index e8777b633..2436deb35 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/TaskWorkLeaf.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/workorders/entities/TaskWorkLeaf.java
@@ -1,10 +1,16 @@
 package org.navalplanner.business.workorders.entities;
 
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 public class TaskWorkLeaf extends TaskWork {
 
+    private Boolean fixedHours = false;
+
+    private Set<ActivityWork> activityWorks = new HashSet<ActivityWork>();
+
     @Override
     public Integer getWorkHours() {
         int result = 0;
@@ -28,25 +34,17 @@ public class TaskWorkLeaf extends TaskWork {
         return true;
     }
 
-    public void remove(TaskWork taskWork) {
-
-    }
-
     @Override
     public TaskWorkContainer asContainer() {
         TaskWorkContainer result = new TaskWorkContainer();
         result.setName(getName());
         result.setInitDate(getInitDate());
         result.setEndDate(getEndDate());
-        result.setActivities(getActivities());
+        // FIXME
+        // result.setActivities(getActivities());
         return result;
     }
 
-    @Override
-    public void replace(TaskWork old, TaskWork newTask) {
-        throw new UnsupportedOperationException();
-    }
-
     public void setWorkHours(Integer workingHours) {
         List<ActivityWork> activities = getActivities();
 
@@ -63,4 +61,37 @@ public class TaskWorkLeaf extends TaskWork {
 
         setActivities(activities);
     }
+
+    public void setActivities(List<ActivityWork> activities) {
+        this.activityWorks = new HashSet<ActivityWork>(activities);
+    }
+
+    public void addActivity(ActivityWork activityWork) {
+        activityWorks.add(activityWork);
+    }
+
+    public void deleteActivity(ActivityWork value) {
+        activityWorks.remove(value);
+    }
+
+    @Override
+    public List<ActivityWork> getActivities() {
+        return new ArrayList<ActivityWork>(activityWorks);
+    }
+
+    @Override
+    public void forceLoadActivities() {
+        for (ActivityWork activityWork : activityWorks) {
+            activityWork.getWorkingHours();
+        }
+    }
+
+    public void setFixedHours(Boolean fixedHours) {
+        this.fixedHours = fixedHours;
+    }
+
+    public Boolean isFixedHours() {
+        return fixedHours;
+    }
+
 }
diff --git a/navalplanner-business/src/main/resources/org/navalplanner/business/workorders/entities/WorkOrders.hbm.xml b/navalplanner-business/src/main/resources/org/navalplanner/business/workorders/entities/WorkOrders.hbm.xml
index e5f1e5244..bfdc03d3c 100644
--- a/navalplanner-business/src/main/resources/org/navalplanner/business/workorders/entities/WorkOrders.hbm.xml
+++ b/navalplanner-business/src/main/resources/org/navalplanner/business/workorders/entities/WorkOrders.hbm.xml
@@ -23,14 +23,13 @@
         <id name="id" type="long" access="field">
             <generator class="native" />
         </id>
-        <set name="activityWorks" access="field" cascade="all">
-            <key column="PARENT_TASK" not-null="false"></key>
-            <one-to-many class="ActivityWork" />
-        </set>
 
         <property name="name" access="field" />
         <property name="initDate" access="field" />
         <property name="endDate" access="field" />
+        <property name="mandatoryInit" access="field" />
+        <property name="mandatoryEnd" access="field" />
+        <property name="description" access="field" />
 
         <joined-subclass name="TaskWorkContainer">
             <key column="TASKWORKID"></key>
@@ -43,6 +42,13 @@
 
         <joined-subclass name="TaskWorkLeaf">
             <key column="TASKWORKID"></key>
+
+            <property name="fixedHours" access="field" />
+
+            <set name="activityWorks" access="field" cascade="all">
+                <key column="PARENT_TASK" not-null="false"></key>
+                <one-to-many class="ActivityWork" />
+            </set>
         </joined-subclass>
     </class>
 
@@ -50,6 +56,10 @@
         <id name="id" type="long" access="field">
             <generator class="native" />
         </id>
-        <property name="workingHours"></property>
+
+        <property name="workingHours" access="field" />
+        <property name="percentage" access="field" />
+        <property name="hoursPolicy" access="field" />
+
     </class>
 </hibernate-mapping>
\ No newline at end of file
diff --git a/navalplanner-business/src/test/java/org/navalplanner/business/test/workorders/services/ProjectWorkServiceTest.java b/navalplanner-business/src/test/java/org/navalplanner/business/test/workorders/services/ProjectWorkServiceTest.java
index afe1a6d20..77ed835aa 100644
--- a/navalplanner-business/src/test/java/org/navalplanner/business/test/workorders/services/ProjectWorkServiceTest.java
+++ b/navalplanner-business/src/test/java/org/navalplanner/business/test/workorders/services/ProjectWorkServiceTest.java
@@ -1,5 +1,13 @@
 package org.navalplanner.business.test.workorders.services;
 
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.CoreMatchers.notNullValue;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertTrue;
+import static org.navalplanner.business.BusinessGlobalNames.BUSINESS_SPRING_CONFIG_FILE;
+import static org.navalplanner.business.test.BusinessGlobalNames.BUSINESS_SPRING_CONFIG_TEST_FILE;
+
 import java.util.List;
 
 import org.junit.Test;
@@ -20,14 +28,6 @@ import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 import org.springframework.transaction.annotation.Transactional;
 
-import static org.hamcrest.CoreMatchers.equalTo;
-import static org.hamcrest.CoreMatchers.notNullValue;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
-import static org.navalplanner.business.BusinessGlobalNames.BUSINESS_SPRING_CONFIG_FILE;
-import static org.navalplanner.business.test.BusinessGlobalNames.BUSINESS_SPRING_CONFIG_TEST_FILE;
-
 /**
  * Tests for {@link ProjectWork}. <br />
  * @author Óscar González Fernández <ogonzalez@igalia.com>
@@ -171,7 +171,7 @@ public class ProjectWorkServiceTest {
                     TaskWorkContainer containerReloaded = (TaskWorkContainer) reloaded
                             .getTaskWorks().get(0);
                     assertThat(containerReloaded.getActivities().size(),
-                            equalTo(0));
+                            equalTo(1));
                     assertThat(containerReloaded.getChildren().size(),
                             equalTo(1));
                     TaskWork leaf = containerReloaded.getChildren().get(0);