I was able to find the right tools to inject an updated CPU-list extracted from the AsRock Conroe945-DVI beta BIOS 1.91 available from a German website.

The updated CPU list is injected into and replaces the CPU-list in the standard Asus BIOS 1002. I then boot with a flash-usb drive with the modded bios named c90s.rom in the root of the drive. Power up and press ALT+F2 to start auto-recovery flashing using EZ-flash which will search optical and USB-drives for a bios file (c90s.rom).

Reboot, enter BIOS, load setup defaults, save.

Tested working with E5200 and E7300 ES.

PM me for a copy of the updated BIOS, I call it 1003.