After playing with the configuration files and testing, I have decided not to use EC2 auto-scaling with my JMS tier under JBoss EAP 5.1.2.
Let's say that a new JBoss JMS node comes online using auto-scaling. What does it take to get this new node visible to the rest of the JMS cluster? Based on the documentation for JMS, it appears that I would have to modify several configuration files across all nodes to make this happen. I would then have to restart those nodes because the file 'jbossts-properties.xml' is statically loaded at startup and is not hot-deployable. That would defeat the purpose of bringing a new node online which is to increase capacity. It looks like my team is going to establish a separately managed JMS tier running only queues, topics, connection factories, etc., and put any application logic on auto-scaled JBoss app server nodes hosted outside of the queues, topics, etc.