It's been quite a while since i integrated ArjunaTS with jboss 4.0.3SP1. But I did it on trial & error basis and made it work upto certain level. But there were some issues like i couldn't set the default transaction timeout. I tried every means but there were unpredictable result. However, I'v assumed it was some problem with my integration and bypassed it using BMT and setting tx timeout programatically. Now, I'm interested to know if the arjuna transaction manager is shifted as the default tx manager in any release of jboss. Or any fix/reason of the timeout behavior is there.
There was a timeout issue that may be related. It was fixed in 4.2.1 I think. Check the release notes or JIRA issues.