I took a quick look. If you have your B2 configured to act as an NAS (network file server) and can "see it from your PC" and both read & write to the B2 drive from your PC, then it looks like "Tune Up" should work. From the web page, it's not clear that it supports FLAC files though (might just be mp3?) or whether its cover art tagging will work with the B2. And you'll need to run "Scan" from the B2 menus when you are done.
There is a free demo version - give it a try and let us know?