Sorry for the delay. You are correct that the only remote classloading facility in Remoting 2 is from server to client. I'm not sufficiently familiar with Remoting 3 to give you an answer, but it's possible that Remoting 3 is more symmetric in this regard. However, you would have to upgrade to AS 7 to use Remoting 3.
I have moved this thread to the Remoting Users forum.