ASUS P5N32ESLI/ BACK DATE BIOS

[TurboChilled]

HI ALL, i have a asus p5n32-e-sli, i download a bios from here posted which was to allow xeon E5450 mod...unfortunatley the bios i have is the latest 0903....it will not allow any back dtaed bios to be added as warning displayed.....now its bios is displayed as phoenix award on the opening bios screen...i have not alot of heads up on this so i know how to use easy flash in the bios itself......hence the error....removed the bios chip battery the jumper every thing to no avail.....is this actually possible as its cpu socket is modded and the xeon chip adaptor is on the chip correctly ready to go. i am using a duo 2.4 to enable usage to boot and 2 gigs of pc8500 1066mhs ocz sli memory and 1 gtx 26o until sli is enabled...thanks to anyone who can shed some light..this is for a stand alone render rigg hence the xeon mod required