This is not guaranteed to work, but it's worth a shot:
Open up WinAmp.
Right-click on the player.
Go to Options -> Preferences -> General Preferences - Global Hotkeys.
Check the box for Enable.
Yes, I know the hotkeys appear to be intended for ctrl+alt hotkey combinations, but this is what I had to do to get WinAmp to recognize signals from my MS keyboard's media keys (the ones that look like the rewind, fast forward, play, stop, etc keys on a typical remote). The media keys on my keyboard work on the Creative MediaSource audio player too, so it's possible that these things are somewhat standardized and it'll work in reverse too (i.e. a Creative remote will work w/WinAmp). If you find that certain functions don't appear to work, then check to see what keyboard hotkeys the MediaSource player uses, then set the same mappings in WinAmp.