Auto L canceling isn't necessarily a global code. It's just a modification of values under a character's attributes for each of their aerial attacks. Open up the moveset .pac in PSA, go to attributes, and look for 0x140, 0x142, 0x144, 0x148, 0x150 (at least, I think those are the right values, they're listed there anyways). These are the landing lag values for each aerial (I don't remember which is which though). Just cutting each in half should do the trick.
Because the PMBR has not release a text file for their codes, you cannot put the current manual L canceling code in unless you manually insert it with a GCT->TXT editor. Even then, I'm pretty sure there are some other pieces of code you'll need for it to work properly, much like how just taking their Melee air dodge code won't operate fully.