OK, I've got it. When I looked more closely at the shutdown script I found org.jboss.Shutdown which, when given the correct parameters, does the sutdown quite nicely. However, it is very weak in it's error handling. For instance, if you omit name and password, which i think are shown as optional parms, it throws and then eats a NullpointerException without letting the user know that anything has gone wrong.
shutdown is fixed in 3.0.7