Dissidia 012: Duodecim Final Fantasy

[RayOfSpeed]

Hey there, I've been having an issue trying to get DLC to work. Prologus works just fine, of course, but the Aerith DLC won't seem to work, even though I've dropped the folder it comes in into PSP\GAME and renamed the folder to match the serial of the ISO (ULUS10566 instead of ULES). Anyone care to tut me as to what I've been screwing up?
I'm suspicious it might be a region thing, since I'm using an NTSC copy of Duodecim, but I acquired the DLC from my PAL PSN account.