iMaGe, Trevor is correct in saying that this is just a USB device still, the HW in the Empeg is still doing a lot of the work, and it would be impossible to emulate a host port (like the one on your PC that you can actually plug a keyboard into) in just software.

I actually started on this task as I was looking at how to connect USB devices, and Drakino suggested this may be a nice little warm-up task. For the discussion on connecting USB devices see here, and don't worry as soon as I have this one nailed my focus will switch back to that one.