There is a button inside the cargo area to open the fuel door when the auto latch fails.

 

Seriously!?!? I have the 5 seat version with the cargo buckets, do I have to remove something to get at it? I have not seen anything back there.

 

It is in the owners manual, I do not know its exact location or how to get to it, I think you have to remove the trim piece that covers the tail light and there is a button in there or some such.
But it is in the owners manual, if you do not have that then download the RAVE manual, it has the owners manual as well as the shop manual.