Yeah weird indeed! I've tried google also but with no results.
Also just checked with NAS4Free, and the drives do show up there as well. Was able to create a ZFS Pool after I formatted them (pic below is before).
But according to the documentation I've read, you need to flash the card's firmware to match the driver that's native in FreeBSD. That's why I wanted to update to P17 first. But it seems the P19 is the right one for FreeBSD 10 (which NAS4Free is currently based on). P20, which is also available has documented bugs...
I just wonder if I'll stumble upon problems later on with it flashed to P14, the only one that can actually detect the drives attached. When flashed to P19 the drives wouldn't show up under disk management in NAS4Free 10 nor Windows 7 as I stated. Tricky one.