Steven
I think I need to clarify what you mean by "client package". When I first read your email, I assumed you were talking about creating a package to distribute to clients. In this reference, I was reading "jar file" instead of "package".
But I realise that I am almost certainly wrong: you are using the term package in the same way that Sun use it: to describe the directory structure for the classes.
So RemoteData (and therefore RemoteData_stub) are in the suncertify.server package, and this is where they belong.
Assuming you have a directory structure like:
Then as long as you start your application with
java -cp classes .... the client should be able to find the stub file.
(Change the example directory structure to suit your layout of course).
Likewise, when you package it all into an executable jar file, the client code will be in the same jar as the stub file, so it will be able to find it.
Regards, Andrew