diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/advance/entities/AdvanceAssigment.java b/navalplanner-business/src/main/java/org/navalplanner/business/advance/entities/AdvanceAssigment.java
index 33f5be8ad..f01da794f 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/advance/entities/AdvanceAssigment.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/advance/entities/AdvanceAssigment.java
@@ -1,8 +1,8 @@
 package org.navalplanner.business.advance.entities;
 
 import java.math.BigDecimal;
-import java.util.HashSet;
-import java.util.Set;
+import java.util.LinkedList;
+import java.util.List;
 
 import org.navalplanner.business.common.BaseEntity;
 import org.navalplanner.business.orders.entities.OrderElement;
@@ -15,7 +15,7 @@ public class AdvanceAssigment extends BaseEntity {
 
     private AdvanceType advanceType;
 
-    private Set<AdvanceMeasurement> advanceMeasurements;
+    private List<AdvanceMeasurement> advanceMeasurements;
 
     public AdvanceAssigment(boolean reportGlobalAdvance, BigDecimal maxValue) {
         this.reportGlobalAdvance = reportGlobalAdvance;
@@ -45,11 +45,13 @@ public class AdvanceAssigment extends BaseEntity {
         return this.advanceType;
     }
 
-    public void setAdvanceMeasurements(Set<AdvanceMeasurement> advanceMeasurements) {
+    public void setAdvanceMeasurements(
+            List<AdvanceMeasurement> advanceMeasurements) {
         this.advanceMeasurements = advanceMeasurements;
     }
 
-    public Set<AdvanceMeasurement> getAdvanceMeasurements() {
-        return new HashSet<AdvanceMeasurement>(this.advanceMeasurements);
+    public List<AdvanceMeasurement> getAdvanceMeasurements() {
+
+        return new LinkedList<AdvanceMeasurement>(this.advanceMeasurements);
     }
 }
diff --git a/navalplanner-business/src/main/resources/org/navalplanner/business/advance/entities/Advance.hbm.xml b/navalplanner-business/src/main/resources/org/navalplanner/business/advance/entities/Advance.hbm.xml
index b3b2fa7d6..3975fe971 100644
--- a/navalplanner-business/src/main/resources/org/navalplanner/business/advance/entities/Advance.hbm.xml
+++ b/navalplanner-business/src/main/resources/org/navalplanner/business/advance/entities/Advance.hbm.xml
@@ -33,10 +33,11 @@
 
     <many-to-one name="orderElement" class="org.navalplanner.business.orders.entities.OrderElement" column="ORDER_ELEMENT_ID"/>
 
-    <set name="advanceMeasurements" cascade="all" inverse="true">
+    <list name="advanceMeasurements" cascade="all" inverse="true">
         <key column="ADVANCE_ASSIGMENT_ID"/>
+        <list-index column ="date"/>
         <one-to-many class="AdvanceMeasurement"/>
-    </set>
+    </list>
 </class>
 
 <!-- AdvanceMeasurement -->