No, Vorbis Comments are a wholly different thing from ID3 tags. The point with Vorbis Comments is you make the attributes up yourself, and you can add more than one instance of the same attribute, for example COMPOSER. While ID3 tags have very strict rules and chiefly pre-defined fields, although there is some room for customisation, Vorbis Comments are entirely customisable.
However, most programmes made for tagging MP3 files don't seem to care very much to make use of the full power of Vorbis Comments. In an MP3 tag (ID3) there is only one COMPOSER field, so the programme will only display the pre-defined ID3 fields because most people only care about using ID3 tags.
I'm using Tag&Rename 3.5.7 and it is very good, save for the fact that you can't specify your own tag fields.
I have tried many programmes. The one which got closest to doing what I wanted was MetatOGGer, but it didn't let me add more than one field with the same name.
I guess I'll have to try a command line tagger next!