I have a simular keyboard and I investigated the problem a few months ago.
This is a kernel problem.
You can see it by pressing the keys from the console.
You should get the following errors:
Dec 19 21:06:16 localhost kernel: atkbd.c: Unknown key pressed
(translated set 2, code 0x91 on isa0060/serio0).
Dec 19 21:06:16 localhost kernel: atkbd.c: Use 'setkeycodes e011
<keycode>' to make it known.
Those messages should also appear in the kernel logs.
I explained the problem and gave a 'hack' to solve it in the following
link some months ago:
http://www.linuxgazette.com/node/9028#comment-932
I hope that helps.
Stephane.
