😕 Why?
Firefly generates its own index (songs.db or songs3.db) and only needs the iTunes library file for playlists.
Thats where exporting playlists as m3u in media monkey comes into the equation.
Point Media Monkey at your music library, set up your playlists and then export them to Firefly using the m3u format.
If Firefly is set to process m3u files and wma is on the list of file extensions then you should have no problems.
As an added bonus, Media monkey understands aac (just not the iTMS DRM protected variety)