Answer:Please follow below SOP to install Windows Vista/7 64bit OS on the RAID volume:
Step 1: Flash BIOS to latest version.
Step 2: Connect all HDDs then do below settings:
Set [SATA Mode] as [RAID Mode]
Change [Onboard RAID 3TB+ Unlocker] to [EFI Compatible ROM]
The options are located in BIOS > [Advanced] > [Storage Configuration]
Then press F10 to save settings.
Step 3: Press F11 during boot up and choose boot to [Built-in EFI Shell].
Step 4: Key in "drvcfg”, and you will see the information like below:
Drv[4E] Ctrl[B5] Lang[eng]

Step 5: Key in "dh [Drv number]”, for example: key in "dh 4E”.
Step 6: Key in "drvcfg –s [Drv number] [Ctrl number]” to enter Raid Utility.
For example: key in "drvcfg –s 4E B5”

Step 7: Choose [Logical Drive Main Menu] to set up Raid Drive.
Step 8: Choose [Logical Drive Create Menu] to create a Raid Drive.

Step 9: Choose [Usable Physical Drive List] to select Raid HDD.

Step 10: Press Space on keyboard to toggle checkbox.

Step11: Choose [Ld Size setting], and key in the Raid size.
Step12: After set up Raid size, please click [Start to Create]

Step13: Press "F10” to Exit Utility.
Step14: During reboot, please press "F11” to enter Boot Menu.
Choose UEFI: CD/DVD Drive

* This option only shows on Windows7 64bit and Vista 64bit OS.
Step 15: Follow Windows Installation Guide to install OS.
Please load latest SATA RAID driver ver.3.3.1540.22 during OS installation from our website
Step 16: Install latest drivers from ASRock website.