Storing media on a TerraStation?

I want to store my music and photos on my Buffalo TerraStation but am hitting
problems. I can access the music and photos directly from Windows Media
Player 11 on both a Vista and XP machine but I cannot share them with my Roku
or XBox 360. It's as if the Windows Media Sharing service cannot access the
remote network folders. If the files are local it works fine, but move them
onto the TerraStation and media sharing stops. In both cases WMP 11 detects
and loads the library fine.

Any ideas?