Shoutbox

So did you have a look in the hidden folders on the iPod to make sure that there isn't any music?  I think that's what you meant by the F01, etc.  If there is music on it there are programs that you can find on the net to get the music off so that you can back it up (I keep a copy of the music either on my PC or disk just in case).  If this doesn't help I really don't know how you can get the music back.

Once you have the music back you can just use the iPod updater to reset it all and iTunes should recognise it again but DO NOT do this before you get your music off or it will wipe it for good.

Hope it works out for you.