I am experiencing the same problem. I am migrating from Glassfish to JBoss and I want to maintain the dependency injection of the PersistenceContext into the stateless session beans so that they can perform database manipulation via JPA. I am using JBoss AS 7 (Final) with the "standalone" configuration.
I have several stateless session beans and one datasource that are configured in the exact manner outlined by the thread poster Raphael. Upon deployment, all beans receive the "Services with missing/unavailable dependencies" error.
However, if I remove the @PersistenceContext annotation from the EntityManager class variable in one bean then that one bean does NOT fail. (However, now EntityManager is null and any calls to it, obviously, would fail. I was just experimenting.)
Does JBoss AS 7 even support @PersistenceContext?