Multimedia keyboards
Here is an excellent article on setting up multimedia keyboards in KDE.
http://ale.freeshell.org/articles/hotkeys/hotkeys.html
As manufactures don't make Linux drivers for multimedia, it has to be done by hand; manually. This articles explains it. I have used it before but didn't like how it didnt display an On Screen Display (OSD) so I used Acme in Mandriva. Well both SuSe and Kubuntu (my current distro) couldn't compile Acme so I had to use this method again. what I have done no though is use a little app called "xosd". This has a command called "osd_cat" which just prints to the screen a text file. With some fiddling I have got a louder, softer and mute python scripts that do the what they claim plus put out an OSD. I am going to put these files up as soon as I have converted the mute bash script from the article to python.
The reason I went with Python is it does floating point arthimetic where as bash doesn't too well. I needed this to give a good percentage that your volumne is currently at.