Asus Motherboard P5MT-S - Manual (Page 106)

5-6 Chapter 5: RAID configuration
4. Select all the drives required for the RAID set, then press <Enter>.
The configurable array appears on screen.
3. The ARRAY SELECTION MENU displays the available drives connected
to the SATA ports. Select the drives you want to include in the
RAID set, then press <SpaceBar>. When selected, the drive indicator
changes from READY to ONLIN A[X]-[Y], where X is the array number,
and Y is the drive number.
The information of the selected hard disk drive displays at the bottom of
the screen.