Anybody Use Keyboard Volume Control for Monitor Levels?

I've been investigating the use of a keyboard or USB volume control to adjust the level of my sound card output.  I think this is a dead-end pursuit (at least as long as I'm still using XP), but I thought I'd see if anyone had some ideas.  I already have a Microsoft keyboard with a volume control on it.  Now, I have not installed the keyboard drivers, so that could be the reason it has no effect.  But I'm guessing that even with the drivers installed, my sound card, an M-Audio 2496, will not recognize the keyboard commands to increase/decrease the level.
 
A second potential solution is a stand-alone USB-connected knob (widely available for about 30 bucks, search on "usb volume control" if curious).  The problem with this is that it requires keyboard equivalents to configure the response.  The M-Audio mixer panel has no keyboard shortcuts to alter volume (at least that I'm aware of).  Furthermore, even it it did, I'm wondering if it the mixer window would only respond when it had focus, which would defeat the whole purpose.
 
The final factor is XP.  Does Windows 7 bring anything to the table in the area of a global volume control capability that XP doesn't have?
 
So, if anyone has advice to offer in this area, it'll be thoroughly appreciated.