This is being changed for AS7-566 (https://issues.jboss.org/browse/AS7-566). The call to PersistenceProviderAdapterRegistry.putPersistenceProviderAdaptor, will be more dynamic, so that other peristence providers can be accessed.
You could register on AS7-566 for notifications, so you will know when the changes are merged into the AS 7.0.1 master. Most of the changes are in https://github.com/scottmarlow/jboss-as/commits/master (need more testing).