Im gonna have to lend a friend of mine my wiimote, and a few of my games(aka, Muramasa) and my gamecube backups can stil be played with my Gc controller...BUT alas, i can't find anyway to launch USB loader GX off HBC
If you have Pre(Prii)Loader installed, you can direct it to start up where ever you like, specifcally your loader program. Assuming your USB Loader supports GC control pad, you should be good to go. Enjoy