Sorry I can't edit my previos post.

Had a play with MAPS and I think I see your problem, the 18F*6K22 has a 12 ADC and 18F*431 has Motion Feedback Module. There are no PIC18F's with USB and Motion Feedback Module. There are however, 17 PIC18F's with 12 bit ADC and USB. If you are using the MFM then you have no choice but to go serial.

Most PC's don't have serial ports so that might help you find your emulated one. If not, you're going to have to ask the user or maybe trial and error?

George