Boot off sata dvd drive?

[mannieg]

Does anyone know if it is possible to boot off a SATA attached DVD drive on an Abit AN7 motherboard (with built in SiliconImage 3112a SATA controller)?
Currently I am running with Abit BIOS 1.9 and SiliconImage BIOS 4.2.47. When I configure the motherboard BIOS to enable RAID both my SATA hard disk and my SATA DVD drive are recognized during bootup but the system always tries to load the OS from the SATA hard disk. (I also have an IDE hard disk and IDE CD drive attached to motherboard.) If I change the SATA channels around, the system still tries to load the OS off the SATA hard disk. There does not seem to be any Abit motherboard BIOS setting I can configure to get the system to boot off the SATA DVD drive. It would appear that my only hope would be to upgrade the SiliconImage BIOS to 2.4.50 or higher and hope that there is additional functionality in the later BIOS.
However there is always some risk in doing this (CBROM SiliconImage BIOS into Abit 1.9 BIOS) and it would be helpful to know in advance that I will achieve my aim and be able to boot of the SATA DVD drive.
Any help would be greatly appreciated.
Thanks & regards,
Mannie