I can't answer this question - but for tagging flac files why not use the mp3 tagger (free). Mp3tag - der universelle Tag Editor (ID3v2, MP4, OGG, FLAC, ...)
(This is in German but click on the Union Jack on the top of the screen on the website for English version).
Excellent program -- tags FLAC just fine -- you can also play in Win Amp or other fLAC supported devices.
Also has a Windows explorer shell so it might do what you need too.
Enc typical layout of flac tagged files
I also I stream my FLAC music into a "Squeezebox" device to play anywhere in the house. The tags show on the device what I'm playing too. Logitech - Wi-Fi Music Players