Media Keyboard adds multimedia keyboard support to VLC, Winamp Classic
Media Keyboard 2 is a free Windows utility that adds support for all of those media players, plus a few more. Just install Media Keyboard and run it and you should be able to control each media player using your multimedia keys. You can register the app to start with Windows if you expect to use this feature a lot.
Make sure not to change the hotkeys for the media player or your multimedia keys may stop working. Of course, if you're using a media player like VLC that supports hotkeys, you may not find much need for the mutlimedia keys in the first place.