thanks, logical thinker.
crap, now i've put them on and gone to 楽曲ダウンロード、 the list is empty. then i clicked on ”ダウンロードした楽曲評価 And The data reading error comes up. (but i guess i wouldn't have any ratings on non-existent songs)
Fantastic.
Now i'll try the *add to custom* thing but i doubt...