I checked the calculator, the sum of my drives are less then 2TB, as I stated I have 12x 146GB and 2x 36GB, it comes to 1.46TB only.
About H/W RAID support - according to DSS docs I can't manage disks and RAID volumes from the management GUI, which is OK for me for now, I know it works because I have another test system with DSS Lite v6 working with older Dell PE2850 server and the hardware RAID no problem.