Exporting Discog Expression Tag to MC14 Database

I'm using the Discogs and Pone Script... to input tags into my MP3 files. Also I'm using J River Media Center 14 (FYI), which has a lot of field, composers, mixartist, bios, etc included.

Here's what I'm trying to do: I want to include the Discog mixartist and Tracklist information in my tags.

For example, Patrice Rushen (Album: Patrice)...

1 Music Of The Earth 3:58
Acoustic Guitar - Abraham Laboriel
Backing Vocals - Pauline Wilson , Roy Galloway , Syreeta Wright Robertson*
Backing Vocals, Electric Piano [Rhodes], Synthesizer - Patrice Rushen
Bass - "Ready" Freddie Washington*
Concertmaster - Jerry Vinci*
Drums - James Gadson
Guitar - Al McKay , Marlo Henderson
Percussion - Paulinho Da Costa
Saxophone [Alto] - Kim Hutchcroft
Saxophone [Tenor] - Larry Williams
Trombone - Bill Reichenbach (2)
Trombone [Bass] - Maurice Spears
Trumpet - Oscar Brashear , Raymond Lee Brown*
Written-By - Angela Rushen

When I download the info, Mixartist, I can see the Tag under under extended tag. It shows in my fields column in MP3Tag, but I can't get it to show in the field for MC-14.

I've created several new fields within MC14, but this particular field will not show.

From reading your FAQ page, I think it has to do with mapping the extended tags fields. Can someone help in determining where the data is being filed.