trouble with Audirvana and multipl artist tag

[pask]

Beck,

i've downloaded metadatics to give it a try, and ad multiple artists to trackartist tag. it's actually working very nice and metadata are recognized via MinimServer and Audirvana, on both MP3 and Flac, but not for M4P, Audirvana return me the artist group as one...
I should try to contact th developer instead, I think the problem is coming from this app.

Thanks, say hi if you come around Nice, south France, to get a drink with some music