I had the same problem with a Compaq laptop. It has something to do with the way Windows recognizes the command that comes when you press the buttons. Explorer recognizes it but LS doesn't. I was able to get them working by mapping them to a hotkey. I'll see if I can remember how I did it. If not someone else here should know.

Heh, should of looked further in the forum: http://www.litestep.net/index.php?section=4&action=view&catId=1&id=3238