EJB 2.1 Unit testing with compatible mock framework

We have an application which has the EJB with legacy version (EJB 2.1). We need to implement unit testing for the EJBs. The code base is very large (especially for ejbs in our application), so we are not going to migrate to 3.x version of EJB. The requirement is to use the mocking framework. We are using JBoss4.2.2_GA

I have researched in all of the forums, but could not find a proper combination of mocking framework suitable for EJB 2.1.

What I am looking is to get an information for below two points. 1. Can we able to unit test EJB 2.1 with mocking framework? 2. If yes, please suggest the compatible mocking framework (any example references are highly appreciated)?.

Thanks, Sree