Middleware Client Server RPC RMI implementation in Java

Hi, I need the attached program done in Java. It's basically a server / client program. The server simply adds or subtracts two numbers sent by the client. Pretty simple uh? However, the hard part is this: You CANNOT use the existing RPC or RMI packages in this project. That is, you ned to design and implement the client-stub, skeleton and dispatcher fro the remote objects, as well as the communication part and remote reference module (RRM) Please give me a quote for this and when you can have it done. Thanks.