I have tried replacing the jar as you said in Wildfly 8.0.0 Final. Everything works as expected now.
Thanks a lot for your help in solving this problem.
For your information I have tried with Wildfly 8.1.0 Final and experienced the same problem I had with Wildfly 8.0.0 Final. Tried to use the same jar you suggest in your post but it seems not to be useable.
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