This message may come a little late, but I just got a 5D MIII after shooting for a couple of years with a T2i. I still edit in FCP 7 so I was looking for a way to log and transfer files from both cameras.
I updated the EOS plugin and was able to transfer MIII footage. Not so lucky with the T2i footage.
I repeated the T2i hack *after* updating the EOS plugin. As today, it is the 1.4 version.
It’s woking like a charm.
I hope it comes handy if you’re still wondering.