"ch11s01" wrote : Warning | | The type of each value must be specified using either the elementClass or type/class attribute in order for the collection to be created. Which I already did in the annotation. I agree that MC is pretty dumb to not be able to create meta data that amounts to this: :-P <bean name="PersistenceUnitDeployer" class="org.jboss.jpa.deployers.PersistenceUnitDeployer"> | <property name="defaultPersistenceProperties"> | <map keyClass="java.lang.String" valueClass="java.lang.String"> | <entry> | <key>hibernate.transaction.manager_lookup_class</key> | <value>org.hibernate.transaction.JBossTransactionManagerLookup</value> | </entry> | </map> | </property> | </bean> View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4162068#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...