Hmm, it's worked on all my 3DS games, certainly works on Awakening (Just soft resetted cause Maribelle got Lethality'd while I was taking her through her last class >_>) Should work if you hit them simlutaniously and if you hold all of them down at once.
IIRC, with the American demo, once you got to the end, it'd take you back to the main menu to start again, so you could keep playing it over and over that way, as that still takes only one use.