I have an EJB A;
EJB A call the RMI client which will connect to the RMI server.
The RMI server will calls EJB B for B's service;
EJB A and EJB B are in the same EJB container.
The applicaton server I using is BEA weblogic 7.0
I am not sure why you need to specify all this when all the EJBs are in same container. The thing is this is what container does. But from you point-of-view you just need to get the InitialContext get JNDI object mapping refference and make the EJB calls.
with EJB 2.0 specs you can have two type of interfaces exposed to client. Remote and Local. If you are pretty sure that down the line you are not going to have these EJBs distributed in different machines then go ahead with Local interface. (The access is through refference). If you are going to use Remote interface and the beans are going to sit in same machine then dont worry about this RMI thing. The reason being weblogic uses itz own t3 protocol for making local calls and it improves the performance too.
Go ahead get the InitialContext get object mapping refference from your JNDI and start using the beans.
hope this helps