place the persistence.xml into the META-INF of your .ejb3 and refer to the other archiv by noting <jar-file>D:/jboss-4.0.4.GA/server/default/external.jar</jar-file> | <persistence xmlns="http://java.sun.com/xml/ns/persistence" | xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" | xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" | version="1.0"> | <persistence-unit name="jta-name" transaction-type="JTA"> | <jta-data-source>java:/DB</jta-data-source> | <jar-file>D:/jboss-4.0.4.GA/server/default/external.jar</jar-file> | <properties> | <!-- some properties... --> | </properties> | </persistence-unit> | </persistence> | View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4015692#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...