User defined tags visible in MediaMonkey

I have a field called Characters Singing for my cast albums and this tag does not appear in MediaMonkey free version. How do I get it to work. I tried their custom field and called it test mm and used COMMENT SONGS-DB_CUSTOM2 with the name test mm in mp3tag but nothing. I found that from 2007 and did not know what to do now. These songs are Flac. Any help would be very much appreciated. Thanks. Characters Singing does appear in Foobar 2000 properties.

Can you create a custom field in MediaMonkey and see what it looks like in MP3tag?

That's because the field you created is used for mp3s while custom fields for FLACs in MM use CUSTOM#. See here: