I would like to know how to configure my 3 HardDrives (600GB each) on RAID 5 connected to SAS controller to work smoothly with PremierePro CS4. Mainly to store scratch disk, and all preview files, etc..

At present it shows as one big hard drive in C:\ It shows as follows:

OS(C 0.98 TB free of 1.08TB

I would like to have at least one HDD out of 3 to store my scratch disk files and preview files...

I have installed only CS4 Master Collection + Windows 7 64bit Ultimate as OS in this machine.
Following is my system configuration:

Intel Xeon E5620, 2.4GHz processor/12M Cache, 5.86GT/S, QPI, Turbo, HT, 4C
Intel 5520 Chipset
12GB DDR3 RDIMM Memory,1333MHz, ECC
Three 600GB (15000rpm) SAS HardDrives
Perc6/i SAS/SATA Harware RAID card
All SAS Drives, RAID 5, 3 drive configuration
BlueRayBurner1GB PCIe X16 nVidia Quadro FX3800 ,Dual monitor DP+1 DVI Capable

I am in a little bit strife on this. Any suggestions are much appreciated.