I think I found the source of my error.
There were no exception thrown caused by a typo in my persistence-unit properties. Then I had to update the hibernate jars I was using (core, commons-annotations, annotations, entitymanager) that envers required.
so there was no exception thrown, when you would expect an exception to be thrown? What was the type? And does it work now?
I didnt set the "hibernate.ejb.event.post-*" properties name correctly initially, I had "org.hibernate.ejb.event.post-*" instead and this was silently ignored. That was a simple error from me, but the fact that you can put any property name/values in the persistence-unit's properties without any runtime validation/error is weak IMO, but nothing related to Envers.
When I switched to the proper values I got some exceptions that led me to correct some version compatibility problems between Enverts and Hibernate I was using. Those exception I was expecting initially, but now I know why... ;)
Now everything is working great. Looks like Envers integration will be very straightforward and easy in my project.