As documented on http://hornetq.sourceforge.net/docs/hornetq-2.1.0.Final/user-manual/en/html/appserver-integration.html#xa-recovery

We had a discussion here also : http://community.jboss.org/thread/153211?tstart=0

you basically need to add this to the file:

<properties depends="arjuna" name="jta">
<property name="com.arjuna.ats.jta.recovery.XAResourceRecovery.HORNETQ1"
value="org.hornetq.jms.server.recovery.HornetQXAResourceRecovery;org.hornetq.core.remoting.impl.invm.InVMConnectorFactory"/>

.... all the content that was already there
</properties>

A patch would work fine here.