I don't even know if it's possible to update two entity beans in a single transaction (2-phase commit) with JBoss and MySQL.
I saw a 60 euros problem ticket at www.infutura.com that deals with that question and there is currently no result.
What version of JBoss and mysql do you use?
Sorry for the late reply - I thought nobody would ever reply.
XAPool v1.3.1 (hope it's correct - the latest anyway)
It only happened with create() and coincidentally (or not), I use the auto-generate-pk stuff to generate the PK. The reason I'm trying XA is I want to ensure that updates to EJB and sending of JMS message happen in one transaction so if the EJB fails the JMS message shouldn't be sent at all. I've been searching for a while and still nothing... Guess I'll try it out with Oracle when I have time. Any more ideas?