Works fine for me. Just gave it a try against 5.1.0 GA. Can you post the import statement in your bean code? Also where are you checking that the injected resource is null? Can you post that part too?
I found the problem.
With JBAS 5.0.0.GA, in an ejb service, the resource is already injected in the 'create' method
against by JBAS 5.1.0.GA.
And we refer to the injected resource in this method.
We 've moved the code from the 'create' method to the 'start' method and now it's ok.