Thanks again Andrew (you really read all of these messages! amazing)
Just to see if I understand the limitations:
may not be possible to use external RMI Registry
why? anything related to security policy?
since stubs are local to client, if ever you change server side, you will have to provide clients with new stubs (rather than the client dynamically downloading them as required).
This is because the client is tied to a specific remote interface but the server can use different implementing classes and the client will download them as needed?