Question about gallery

How do you exactly unlock all the “invitation” section in gallery mode? You know, that Mai illustration with a shit ton of chibi-characters playing around [S]her boobs[/S] her.
At first, every time I finished the game and/or clear some missions I was getting more and more pieces unlocked, but I got totally stuck at 66%. After that, getting the remaining endings and more missions did nothing else.
I’m guessing you have to get records/advance on every mode, so this is what I already have:

-All default team endings (arcade)
-All default team endings (story)
-100% story mode
-About 9 edit team special endings (arcade)
-About 42% of the missions (I doubt I’ll get past 60%, I’m very bad at execution)
-Cleared time attack and played survival a couple times
-Customized some characters (4-5)
-Played some random player/ranked matches (VERY few cause the online totally blows for me)

Any clearer info from people who has more percentage than me will be appreciated. Thanks!

The invitation is unlocked by offline achievements (I guess trophies on PS3). Each one you earn unlocks 3-4% of the invitation. Online achievements (50 wins, 100 fights, etc.) don’t add anything.