The special buttons for things like volume control and mute are not part of a standard keyboard layout, so there will have to be some way of telling the operating system what to do when they're pressed. This means drivers will be required.
A quick check on the HP site shows that they don't officially support Linux for this model;
http://h20000.www2.hp.com/bizsupport...753&taskId=135
So, unless anyone knows of an opensource equivalent then you may be stuck with Kmix as your only control method.
I don't really know enough about the special keys to know whether it's a motherboard driver or a keyboard driver that you need. But you can bet it's not a universal one. That would be too easy :-)
Regards,
Richard.