It's all animation from Maya as either tga or psd frames. In CS6 Despite me setting the "Preserve Trans" in the codex settings it still doesn't render it. Basically, instead of a transparent bg. It comes in as black.
I just did another test with CS4 and it works in there! in CS4 the codec options are within the AE modal window as opposed to another separate modal window in CS6.
-- CS6 project screenshot