No, looks like he bought this
pre-made server, configured a RAID6 array using its hardware RAID controller (which, of course, you should never do with FreeNAS), and installed FreeNAS to the disk array (which, of course, you should never do with FreeNAS). The latter is the reason he can't see his disks; he's already used them. If he'd read the install screens (forget about the manual, just the installer screens would have sufficed), he would have known better.
@cquintana, you really need to read the manual and some of the sticky threads around here. In addition to the problems I've already mentioned, if you intend to use anywhere near the capacity of that server, you're going to need lots more RAM.