Gigabyte GA-8S648FX and P4 Mobile 2.2 dilema

Ok, I have a P4 Mobile 2.2ghz that I've been trying to get to run on my brother's Gigabyte GA-8S648-FX mobo. We updated the BIOS to the lastest version and installed the chip but the system will not POST. Before the BIOS flash it was picking the chip up as a Xeon and was running it at 12x100. I don't know a great deal about Intel chips as I'm a pure AMD guy so I'm hoping that someone here can shed some light on this. Anyone know why this won't work or any possible solutions on getting it to? Thanks!

-Fb