This might be a long shot, but I need to know...

anybody tried connecting an mp3 player that's NOT an iPod / phone to the Mini Visual Boost?

I've got a Sony one, and when I plug it into the USB socket, it just refuses to acknowledge its existence.
If I plug it into the Aux Jack (headphone style socket), I can play any of my music just fine, but have to control it via the player, not the Mini...

Just about to try a firmware update on the player, to see if that will help, and I've noticed that's there's a kind of 'settings' file on the player (capability_00.xml) which appears to be editable, and a line in that file states that <Storage max-full="100" type="MTP"/>
Which I'm guessing means that MTP (media transfer protocol) mode is turned on, which the Mini apparently needs.
Anybody round these parts have any suggestions?
(...I don't want to turn to the apple dark side...)