I've no idea what the answer to your question is, but what I do with multi-disc albums is frig the track number, such that disc one was tracks numbered as 101-199, disc two as 201-299 and so forth. Then drop all the tracks into a single directory (and make sure the Album tag for all MP3s is the same). I reckon just about all MP3 players can deal with that.
Register
RE: Does it support disc x of y tags
I've no idea what the answer to your question is, but what I do with multi-disc albums is frig the track number, such that disc one was tracks numbered as 101-199, disc two as 201-299 and so forth. Then drop all the tracks into a single directory (and make sure the Album tag for all MP3s is the same). I reckon just about all MP3 players can deal with that.