Paul, in this particular case I'm using the composer field at the track level. I added that manually.
double6g, so far VS has been able to handle whatever I've needed. The issue is not getting the information into the MP3s; it's getting the information into Acoustica Label Maker.
The issue with VS is that the information it puts in m3u files is limited to what it would put on a CD. Acoustica Label Maker reads the file just fine; it just doesn't have everything I want.
I don't know what the format definition of an m3u file is, so I don't know if it could potentially hold all of the information or not.
I don't think mp3tag will create an m3u, playlist, or text file. Using VS to put the tags into the MP3s, and then having Label Maker import it from those MP3s, works.
The attachments show what Label Maker (and other programs, I presume) can do with the tags VS can put into MP3s. Note that the information in each MP3 is a merge of the track level and album level information. I put the artists' names in the way I did to save space in the track listings. I captured the track listing screen in two chunks, because the window is fixed in size.