Hi,
being honest, I stopped running the RAID array after I had done my testing and written the review and I have almost forgotten what messages I had displayed on the monitor.
Depending on what other HDD(s) and or DVD/CD Drives you have and how they are configured (IDE, AHCI) will depend on what you get shown during the POST phase of start up. The system will search for HDD(s) and other drives but it won't see the RAID array in the normal manner and it doesn't report the RAID as a Drive.
If everything is working OK and all of your other drives are being reported correctly from within the OS then it is pretty safe to assume it is just a quirk in the way BIOS is reporting things.