XTS will be deployed into JBossAS as a .sar and may be deployed and undeployed over the lifetime of the AS instance. The recovery code is always resident in JBossAS, it starts as part of the transaction service. Thus it needs to be able to support XTS registering and unregistering a recovery module for XTS transactions whilst the system is running.
Right now recovery modules must be in the jbossjt(a|s)-properties.xml file and are read at startup only. Allow them to be registered and unregistered programatically also. May need fixes for concurrency control, as the list of registered modules is iterated during recovery passes and concurrent modifications are a Bad Thing.