Well this is exactly what I would do.
Using your manual Find out if and what ports are RAID Only (IF there are specific ones) Then attach the raptor to the Non RAIDed one. Format the raptor and install the OS. Once its all setup and the OS is fine, turn off the computer, attach the other two drives to the RAID Ports,turn on computer, enter CMOS setup, find the option to enable RAID, enable it, save settings, then enter the RAID setup utility after POST by hitting a given key stated on screen. Then through that utility you can add those two drives to the array and select the RAID Type. Save settings. Once windows boots up, you can enter Disk managment through administrated tools in control panel. Select the Newly created Drive, format it, partition if you wish, then use as storage.