is the drive on port 2 functional? if you swap around ports does it show up and another one disappear? try swapping cables as well.
btw RAID5 on a desktop board/controller is going to go very badly as there is quite an overhead for RAID5 using an integrated controller. There are some computations which will need to be done by the CPU as apposed to a dedicated controller which handles this by itself. So just be prepared for a notable drop in performance once you get it setup.