diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/advance/entities/AdvanceMeasurement.java b/navalplanner-business/src/main/java/org/navalplanner/business/advance/entities/AdvanceMeasurement.java
index a7c6f5d88..ed4c4c6c7 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/advance/entities/AdvanceMeasurement.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/advance/entities/AdvanceMeasurement.java
@@ -41,13 +41,10 @@ public class AdvanceMeasurement extends BaseEntity {
         return advanceMeasurement;
     }
 
-    @NotNull
     private LocalDate date;
 
-    @NotNull
     private BigDecimal value;
 
-    @NotNull
     private AdvanceAssignment advanceAssignment;
 
     public AdvanceMeasurement() {
@@ -56,13 +53,16 @@ public class AdvanceMeasurement extends BaseEntity {
     private AdvanceMeasurement(LocalDate date, BigDecimal value) {
         this.date = date;
         this.value = value;
-        this.value.setScale(2,BigDecimal.ROUND_HALF_UP);
+        if (this.value != null) {
+            this.value.setScale(2, BigDecimal.ROUND_HALF_UP);
+        }
     }
 
     public void setDate(LocalDate date) {
         this.date = date;
     }
 
+    @NotNull(message = "date not specified")
     public LocalDate getDate() {
         return this.date;
     }
@@ -74,6 +74,7 @@ public class AdvanceMeasurement extends BaseEntity {
         }
     }
 
+    @NotNull(message = "value not specified")
     public BigDecimal getValue() {
         return this.value;
     }
@@ -82,6 +83,7 @@ public class AdvanceMeasurement extends BaseEntity {
         this.advanceAssignment = advanceAssignment;
     }
 
+    @NotNull(message = "advance assignment not specified")
     public AdvanceAssignment getAdvanceAssignment() {
         return this.advanceAssignment;
     }
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/advance/entities/DirectAdvanceAssignment.java b/navalplanner-business/src/main/java/org/navalplanner/business/advance/entities/DirectAdvanceAssignment.java
index f8feab600..3bd4dfc93 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/advance/entities/DirectAdvanceAssignment.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/advance/entities/DirectAdvanceAssignment.java
@@ -26,6 +26,7 @@ import java.util.SortedSet;
 import java.util.TreeSet;
 
 import org.hibernate.validator.NotNull;
+import org.hibernate.validator.Valid;
 import org.joda.time.LocalDate;
 import org.navalplanner.business.orders.entities.OrderElement;
 
@@ -51,9 +52,9 @@ public class DirectAdvanceAssignment extends AdvanceAssignment {
         return advanceAssignment;
     }
 
-    @NotNull
     private BigDecimal maxValue;
 
+    @Valid
     private SortedSet<AdvanceMeasurement> advanceMeasurements = new TreeSet<AdvanceMeasurement>(
             new AdvanceMeasurementComparator());
 
@@ -68,6 +69,7 @@ public class DirectAdvanceAssignment extends AdvanceAssignment {
         this.maxValue.setScale(2, BigDecimal.ROUND_HALF_UP);
     }
 
+    @NotNull(message = "maximum value not specified")
     public BigDecimal getMaxValue() {
         return this.maxValue;
     }
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/OrderElement.java b/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/OrderElement.java
index ac03faf1a..fba89ece9 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/OrderElement.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/OrderElement.java
@@ -76,6 +76,7 @@ public abstract class OrderElement extends BaseEntity {
 
     private String description;
 
+    @Valid
     protected Set<DirectAdvanceAssignment> directAdvanceAssignments = new HashSet<DirectAdvanceAssignment>();
 
     @Valid