USB Modes And The Music Folder

I bought a Sansa Clip and when I first plugged it in on a Windows 7 machine it showed all the files in the music folder, one of those was a Playlist folder, plugging it into an XP machine means you have to juggle the USB modes, one mode MTP I can see and open the player as a storage but the Music folder is empty, the MSC mode I can not even get it to register as a storage device and none of the tracks show up in Winamp.

I have checked the manual and I could see no mention of playlist files or how to use them, could someone enlighten me as to how to access them, also are they standard .m3u files?