Adrian points to a discussion on MDB singleton semantics:
MDB Singleton Semantics
(Working with NonJBoss deployments)
Sonic MQ is an industry leading vendor on messaging. They have a tutorial to integrate SonicMQ 6.1 to use with MDBs running on JBoss 3.2.5. The link is:
SonicMQ integration with JBoss
Now an user has reported a workaround to make the tutorial work on JBoss 4.0.1 onwards.
1)Edit the sonicmq-service.xml file in the deploy directory and
2) change org.jboss.jms.jndi.JBossMQProvider to
3) Restart JBoss and the example MDBs will work as advertised.
A great resource to look at configuring MDBs deployed on the JBoss platform to talk to remote queues is.