Thanks. Do I still maintain the old code "as is" and simply put the mappedBy in the new PartnerToRate entity? I'm sorry if the question is dumb but there is not much documentation yet on this topic :-/ and I am sort of a newbie to ejb3. So let me see if I understood this well: 1) I keep the ManyToMany mapping between Partner and OptionRate 2) I add the third entity representing the joinTable and put a mappedBy attribute somewhere in it... Right? Could you please provide a little code as an example of this? Thank you very, very much :-) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3960610#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...