I've got an Entity EJB implemented at EJB Spec 2.0. that I host in my EJB Container. I have a client that would like to use this EJB, but his EJB Container is at EJB Spec 1.1. I would develop a 1.1 Session EJB, and would provide him with these Remote interface components, but I don't know if I create a Session EJB at Spec 1.1, and also host it in my 2.0 EJB Container, would the new 1.1 Session EJB be able to communicate correctly with my existing 2.0 Entity EJB (via the Remote interface components)?
They should be able to communicate with each other. The EJB spec version only matters for developing/deploying the bean into a container -- when it's deployed, the client uses good old RMI to invoke methods and is effectively ignorant of the spec version.