Raw can not be recorded through the hdmi, only the cards.
What I would recommend is either, taking a laptop with you(to dump the footage when you swap cards), or one of the field hard drives.
The hard drives are about as big as a H4n recorder I believe and they allow you to insert your memory card and it copies all of the data to the hard drive. These are small, compact, and seem to be useful. I've never used one, but I've heard good things!