I know nothing (much) about Mac, but in Ubuntu we install exfat-utils and exfat-fuse to make exfat work. Can you do that on Mac? I know it has a terminal but no idea if:
Code:
sudo apt-get install exfat-fuse
... would work in it. Whatever you use to install stuff in Mac, have a look for the two bits of software I've mentioned above.
Just a thought.