It should be done using the ResourceAdapterRepository, as JMX isn't available.
You can check how EJB3/MDBs are hooked up in
You'll need an Endpoint instance that you can call activate() / deactivate() on.
We have a test case here - http://viewvc.jboss.org/cgi-bin/viewvc.cgi/jbossas/projects/jboss-jca/trunk/core/src/test/java/org/jboss/jca/core/inflow/PureInflowTestCase.java?view=log - that also shows how to interact with the repository.
Thanks for your super quick reply! I'll try that.