I assume you're trying to have aMule running on your server and connect to it from a desktop which you're turning on and off -- but you want to leave aMule running. Well, if there's one shortcoming in X remoting, this is it.
You can use VNC to accomplish this nicely. You still need XFree installed for the client libs, but you don't need a server running. Just run a vnc server like this:
vncserver :1 -geometry 1024x768
, it will launch with your default X session, change $HOME/.vnc/xstartup if you wanna do some things differently. Then connect from your desktop box to e.g. server:1, and that's it. You can find vnc servers and clients in your distribution or from realvnc (search Google).