Hi,
I tried controlling my AV gear trough a serial transceiver and I've been stuck on this issue for weeks.
with my device I'm not able yet to learn my remote codes through the wizard, i'm using irrecord.
I can control my device using lirc irsend but i think with usb you might be working on usbhid level.
I let you know if i get any further.
Regards,
Rafik