I want to move my music files from my computer to an external hard drive. I use MusicMatch on my computer and the music library shows up in the My Music file but when I set up the transfer none of these music files show up. How do I either transfer the files directly from MusicMatch to the external hard drive or alternatively get them to show up in My Music when I set up the volume for transfer? Maybe this is very simple but I am totally unfamiliar with using an external drive and the Retrospective manual is virtually incomprehensible.