Same problem here.
Trying to use a genius keyboard, and a ps/2 barcode reader.
The Keyboard Assistant shows up, but it does not recognise the "keyboard type".
Outside of the assistant, not a single key works.
I have already tested the ps/2-usb adapter under windows and linux, and it works well with the keyboard and with the barcode reader.
Under system profile, it gets recognised as:
Generic USB K/B:
ID del producto: 0x0017
ID del fabricante: 0x13ba
Versión: 0.01
Velocidad: Hasta 1,5 Mb/s
ID de la ubicación: 0xfa410000
Corriente disponible (mA): 100
Corriente necesaria (mA): 100
Any clues?