JBoss 5.1.0GA comes with JBM 1.4.3.GA.
It uses a persistence manager to do persistence. It's configured at server side only. I don't think it's possible to make it based on clients (EAR).
Sorry, my mistake, JBM 1.4.3.GA it is of course.
Thanks for your answer. I think we need to accept that different applications need different configurations of JBoss, whether that be for messaging or anything.