How to upload a file through stream?

Now, I meet this problem.
I deploy a Ice server application, and develope a Java GUI client to communicate with it. Now I need to upload a file to remote server. So I define the following Slice file:

module mymodule{
	interface BundleService{
	    string upload(string jarFileName, ByteSeq bytes);
             };
};

It use byte array as parameter, but it is not suitable for large file. I try to use stream, but I can't find any demo on this subject.

Will anybody tell me how?

Thanks.