Which version of RST driver are you using? You can try this one:
I would also check HDD compatibility: http://www.intel.com/support/motherboards/server/s1200kp/sb/CS-032760.htm
Yes i am using RST version 10.6 and after i upgraded to the latest Bios (v.0018) which included a firmware update for the Raid option rom to v10.8 i also used v10.8 of the RST driver with the same results.
I have consulted carefully the Tested operated system and Hardware list but since i had some spare 1TB drives i "had" to used them for storage. The question lies to the fact that my drives are not in this list. In Greece it is not possible to find any of the HDD's included in this list.
So i am stuck....and i dont know what else to try.... maybe a second install will be my only option...
The only think i dont really want to deal with is to RMA the board because it will take weeks or even months for my supplier to exchange it...