We have been working on this. Unfortunately, the current releases of EJB3 do not support access from a 1.4 client. We'll be sure to make sure this capability makes it into the next EJB3 release (RC8)
Presenly I solved this issue with 2.x session bean that acts as a proxy for any EJB3 beans. However I would really prefer a proper solution/support for this case...
I managed to generate a client jar to call remote EJB3 from a JVM 1.4 client, at least in my case (Session Stateless, JBoss 4.0.3SP1 + EJB3 RC6)
I'd like to have your feedback on the way I did it.