You just set them to not RAID, that is how to use them in a Non-RAID fashion.
Sorry, I can't help with OSX concerns though, I use Intel, so I'm not sure about anything on the software side of things for you. No drivers are needed for AHCI or IDE on those ports in windows, default Microsoft ones are used, not sure what would be loaded in OSX?
Why don't you just use the last two Intel ports - SATA2_4/5?