Looks like jbossmq-state.xml has a list of logins/passwords to role mappings.
Maybe you should explain your motivation for removing the subscription? You usually define those in another file. If you want the messages to go away, use JMX to remove them.
My motivation is to create a replication system. On the clients you can subscribe and unsubscribe for some topics. If I unsubscribe a topic so I have to remove the durable subscription on the server (JBoss with JMS). On the clients (JBoss) I hotdeploy a jar file with an mdb for the selected topic. When the client unsubscribe this topic on the server, i delete the jar file in the deploy directory on the client. But i also have to remove the subscription on the Server.