Index: xml/src/main/java/org/exolab/castor/xml/Validator.java
===================================================================
--- xml/src/main/java/org/exolab/castor/xml/Validator.java	(revision 8617)
+++ xml/src/main/java/org/exolab/castor/xml/Validator.java	(revision )
@@ -188,7 +188,8 @@
     
     public void checkUnresolvedIdrefs(ValidationContext context) throws ValidationException {
         if (context.getUnresolvedIdRefs().size() > 0) {
-            String err = MessageFormat.format(resourceBundle.getString("validator.error.class.descriptor.resolver.null"), new Object[] {context.getUnresolvedIdRefs().toString()});
+            String err = MessageFormat.format(resourceBundle.getString("validator.error.unresolved.idref"),
+                    new Object[] {context.getUnresolvedIdRefs().toString()});
             throw new ValidationException(err);
         }
     }
Index: xml/src/main/java/org/exolab/castor/xml/XMLMappingLoader.java
===================================================================
--- xml/src/main/java/org/exolab/castor/xml/XMLMappingLoader.java	(revision 8152)
+++ xml/src/main/java/org/exolab/castor/xml/XMLMappingLoader.java	(revision )
@@ -89,6 +89,7 @@
 import org.exolab.castor.xml.util.XMLContainerElementFieldDescriptor;
 import org.exolab.castor.xml.util.XMLFieldDescriptorImpl;
 import org.exolab.castor.xml.validators.IdRefValidator;
+import org.exolab.castor.xml.validators.IdValidator;
 import org.exolab.castor.xml.validators.NameValidator;
 
 /**
@@ -281,7 +282,9 @@
             FieldDescriptor xmlId = null;
             if (idList.size() != 0) { xmlId = (FieldDescriptor) idList.get(0); }
             
-            if (xmlId != null) { xmlClassDesc.setIdentity((XMLFieldDescriptorImpl) xmlId); }
+            if (xmlId != null) {
+                setClassIdentity(xmlClassDesc, (XMLFieldDescriptorImpl) xmlId);
+            }
             for (int i = 0; i < fieldList.size(); i++) {
                 FieldDescriptor fieldDesc = (FieldDescriptor) fieldList.get(i);
                 if (fieldDesc != null) {
@@ -339,7 +342,7 @@
                     if (!isMatchFieldName(xmlFields2, introFields[i].getFieldName())) {
                         // If there is no field with this name, we can add it
                         if (introFields[i].getFieldName().equals(identity)) {
-                            xmlClassDesc.setIdentity(introFields[i]);
+                            setClassIdentity(xmlClassDesc, introFields[i]);
                         }
                         else {
                             xmlClassDesc.addFieldDescriptor(introFields[i]);
@@ -353,7 +356,7 @@
                     if (!isMatchFieldName(xmlFields2, introFields[i].getFieldName())) {
                         // If there is no field with this name, we can add it
                         if (introFields[i].getFieldName().equals(identity)) {
-                            xmlClassDesc.setIdentity(introFields[i]);
+                            setClassIdentity(xmlClassDesc, introFields[i]);
                         }
                         else {
                             xmlClassDesc.addFieldDescriptor(introFields[i]);
@@ -386,6 +389,15 @@
         return xmlClassDesc;
     }
 
+    private void setClassIdentity(XMLClassDescriptorAdapter xmlClassDesc, XMLFieldDescriptor fieldDescriptor) {
+        xmlClassDesc.setIdentity(fieldDescriptor);
+
+        // modified the validator used for this vield
+        FieldValidator fieldValidator = new FieldValidator();
+        fieldValidator.setValidator(new IdValidator());
+        ((XMLFieldDescriptorImpl)fieldDescriptor).setValidator(fieldValidator);
+    }
+
     protected final FieldDescriptor findIdentityByName(
             final List fldList, final String idName, final Class javaClass) {
         for (int i = 0; i < fldList.size(); i++) {
Index: xml/src/main/java/org/exolab/castor/xml/FieldValidator.java
===================================================================
--- xml/src/main/java/org/exolab/castor/xml/FieldValidator.java	(revision 8617)
+++ xml/src/main/java/org/exolab/castor/xml/FieldValidator.java	(revision )
@@ -52,6 +52,7 @@
 
 import org.exolab.castor.mapping.FieldHandler;
 import org.exolab.castor.xml.location.XPathLocation;
+import org.exolab.castor.xml.util.XMLFieldDescriptorImpl;
 
 /**
  * Handles field validation.
@@ -223,6 +224,13 @@
             return;
         }
 
+        if (((XMLFieldDescriptorImpl)_descriptor).isIdentity()) {
+            if (_validator != null) {
+                _validator.validate(value, context);
+            }
+            return;
+        }
+
         // Prevent endless loop!  Have we seen this object yet?
         if (context != null) {
             if (context.isValidated(object)) {