invisible files on iPod

[Woody]

I resently used my Ipod as a firewire drive. I moved 1.4GB, and then proceeded to delete these files from my drive. However, when I go to iTunes to upload my music, it says that I've allready used those 1.4GB.

I used sherlock, and found that all the files I moved are still on the drive, but are invisible, and I don't seem to be able to delete them.

Can anyone please tell me how to delete them!?

Thanks