Well when you add that folder in media tomb from the GUI, which I'm sure there must be a more direct config file, I have just been to busy to mess with it, you have to sit there as it catalogs and converts everything. My little 30 gig collection was more than I could handle, and it does not seems to have picked up the slack unattended.
In the end what it comes down to is I don't care enough about my media to make this work, ask about my FTP Apache or SSH server sometime I will tell you about how well it's running.