Xperia X10 :: Can't Delete Playlist In Mini Music Player

How do i delete the playlists that i create in my xperia x10 mini. I can't seem to delete them. I created a few playlists then used the media go app to delete them. But when i disconnected the phone from my computer the playlists were still present. I believe that playlists aren't stored on the sdcard. delete these playlists. And can the SE team give a fix in the mediaGo software so that it is able to display the playlists that aren't there on sdcard and allow me to modify or delete them.