lol, yeahUsually they'll just work. I'm on a similar keyboard and they just work with WMP. I haven't tried it with WinAmp yet, though.
yeah...See if it registers in the global hotkey settings for WinAmp. See what dell has to offer with their proprietary drivers. It helps me a lot for shit like this to get solved when I search for the model of the keyboard. Usually some forum will pop up with a solution from a stranger. oh, and obviously you should check if global hotkeys are enabled for WinAmp.