Hi, I'm quite stuck now... Doing a bit of google, I found this: http://stackoverflow.com/questions/675519?sort=oldest According to this, you should remove the entity fields from your PK class and just add the primary key fields of the two entities to it. The relationships "original" and destination" are defined on the "Road" entity. Hope this helps. If not: I cannot help further unfortunately... Wolfgang View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4227836#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...