diff --git a/libreplan-business/src/main/java/org/libreplan/business/common/daos/IntegrationEntityDAO.java b/libreplan-business/src/main/java/org/libreplan/business/common/daos/IntegrationEntityDAO.java
index fe794405e..02dc456b8 100644
--- a/libreplan-business/src/main/java/org/libreplan/business/common/daos/IntegrationEntityDAO.java
+++ b/libreplan-business/src/main/java/org/libreplan/business/common/daos/IntegrationEntityDAO.java
@@ -60,6 +60,7 @@ public class IntegrationEntityDAO<E extends IntegrationEntity>
 
     @SuppressWarnings("unchecked")
     @Override
+    @Transactional(readOnly = true)
     public E findByCode(String code) throws InstanceNotFoundException {
 
         if (StringUtils.isBlank(code)) {
diff --git a/libreplan-business/src/main/java/org/libreplan/business/orders/daos/OrderElementDAO.java b/libreplan-business/src/main/java/org/libreplan/business/orders/daos/OrderElementDAO.java
index c0060e9c6..ceae2321c 100644
--- a/libreplan-business/src/main/java/org/libreplan/business/orders/daos/OrderElementDAO.java
+++ b/libreplan-business/src/main/java/org/libreplan/business/orders/daos/OrderElementDAO.java
@@ -202,6 +202,7 @@ public class OrderElementDAO extends IntegrationEntityDAO<OrderElement>
 
     @SuppressWarnings("unchecked")
     @Override
+    @Transactional(readOnly = true)
     public OrderElement findByCode(String code)
             throws InstanceNotFoundException {
 
diff --git a/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/ExpenseSheetConverter.java b/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/ExpenseSheetConverter.java
index c89c49db3..79ae9f756 100644
--- a/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/ExpenseSheetConverter.java
+++ b/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/ExpenseSheetConverter.java
@@ -45,13 +45,13 @@ public class ExpenseSheetConverter implements IConverter<ExpenseSheet> {
 
     @Override
     public String asString(ExpenseSheet entity) {
-        return entity.getId().toString();
+        return entity.getCode();
     }
 
     @Override
     public ExpenseSheet asObject(String stringRepresentation) {
         try {
-            return expenseSheetDAO.find(Long.parseLong(stringRepresentation));
+            return expenseSheetDAO.findByCode(stringRepresentation);
         } catch (InstanceNotFoundException e) {
             throw new RuntimeException(e);
         }
diff --git a/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/OrderConverter.java b/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/OrderConverter.java
index 09f19b1f6..b7dd48297 100644
--- a/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/OrderConverter.java
+++ b/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/OrderConverter.java
@@ -45,7 +45,7 @@ public class OrderConverter implements IConverter<Order> {
     @Transactional(readOnly = true)
     public Order asObject(String stringRepresentation) {
         try {
-            return orderDAO.find(Long.parseLong(stringRepresentation));
+            return orderDAO.findByCode(stringRepresentation);
         } catch (InstanceNotFoundException e) {
             throw new RuntimeException(e);
         }
@@ -53,7 +53,7 @@ public class OrderConverter implements IConverter<Order> {
 
     @Override
     public String asString(Order entity) {
-        return entity.getId() + "";
+        return entity.getCode();
     }
 
     @Override
diff --git a/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/OrderElementConverter.java b/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/OrderElementConverter.java
index 5f30b2fb8..6a5ffcf7f 100644
--- a/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/OrderElementConverter.java
+++ b/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/OrderElementConverter.java
@@ -42,7 +42,7 @@ public class OrderElementConverter implements IConverter<OrderElement> {
     @Override
     public OrderElement asObject(String stringRepresentation) {
         try {
-            return orderElementDAO.find(Long.parseLong(stringRepresentation));
+            return orderElementDAO.findByCode(stringRepresentation);
         } catch (InstanceNotFoundException e) {
             throw new RuntimeException(e);
         }
@@ -50,7 +50,7 @@ public class OrderElementConverter implements IConverter<OrderElement> {
 
     @Override
     public String asString(OrderElement entity) {
-        return entity.getId() + "";
+        return entity.getCode();
     }
 
     @Override
diff --git a/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/ResourceConverter.java b/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/ResourceConverter.java
index 4f9016741..1f0c74540 100644
--- a/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/ResourceConverter.java
+++ b/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/ResourceConverter.java
@@ -44,9 +44,8 @@ public class ResourceConverter implements IConverter<Resource> {
     @Override
     @Transactional(readOnly = true)
     public Resource asObject(String stringRepresentation) {
-        long id = Long.parseLong(stringRepresentation);
         try {
-            return resourceDAO.find(id);
+            return resourceDAO.findByCode(stringRepresentation);
         } catch (InstanceNotFoundException e) {
             throw new RuntimeException(e);
         }
@@ -54,7 +53,7 @@ public class ResourceConverter implements IConverter<Resource> {
 
     @Override
     public String asString(Resource entity) {
-        return entity.getId() + "";
+        return entity.getCode();
     }
 
     @Override
diff --git a/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/WorkReportConverter.java b/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/WorkReportConverter.java
index e0a3e87f4..2de7e7a01 100644
--- a/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/WorkReportConverter.java
+++ b/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/WorkReportConverter.java
@@ -46,13 +46,13 @@ public class WorkReportConverter implements IConverter<WorkReport> {
 
     @Override
     public String asString(WorkReport entity) {
-        return entity.getId() + "";
+        return entity.getCode();
     }
 
     @Override
     public WorkReport asObject(String stringRepresentation) {
         try {
-            return workReportDAO.find(Long.parseLong(stringRepresentation));
+            return workReportDAO.findByCode(stringRepresentation);
         } catch (InstanceNotFoundException e) {
             throw new RuntimeException(e);
         }
diff --git a/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/WorkReportTypeConverter.java b/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/WorkReportTypeConverter.java
index 01a7a8a15..d4c712324 100644
--- a/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/WorkReportTypeConverter.java
+++ b/libreplan-webapp/src/main/java/org/libreplan/web/common/converters/WorkReportTypeConverter.java
@@ -40,9 +40,9 @@ public class WorkReportTypeConverter implements IConverter<WorkReportType> {
     @Override
     @Transactional(readOnly = true)
     public WorkReportType asObject(String stringRepresentation) {
-        long id = Long.parseLong(stringRepresentation);
         try {
-            WorkReportType workReportType = workReportTypeDAO.find(id);
+            WorkReportType workReportType = workReportTypeDAO
+                    .findByCode(stringRepresentation);
             return workReportType;
         } catch (InstanceNotFoundException e) {
             throw new RuntimeException(e);
@@ -51,7 +51,7 @@ public class WorkReportTypeConverter implements IConverter<WorkReportType> {
 
     @Override
     public String asString(WorkReportType entity) {
-        return entity.getId().toString();
+        return entity.getCode();
     }
 
     @Override