I agree this is annoying. The only option now is to have separate folders for each disc - which is a pain if you don't have it setup that way already.
TPOS does seem to be the disc that most use - here is a nice table of mappings between products:
http://www.mp3tag.de/en/help/main_tags.html
I would toss out that it might should look like:
01 - 01 - First Track of CD1
01 - 02 - Seconds Track of CD1
02 - 01 - First Track of CD2
02 - 02 - Seconds Track of CD2
or
Disc 1 - 01 - First Track of CD1
Disc 1 - 02 - Seconds Track of CD1
Disc 2 - 01 - First Track of CD2
Disc 2 - 02 - Seconds Track of CD2