@rdgrimes - They have simply updated the SATA BIOS with a file you can download from SIlicon Image website. I did the same thing (in fact, using the same file) in my custom SINXP BIOS. In this case, the new SATA BIOS is not a "full" RAID sort of thing like Dee-ehn's apparently was. It is simply an updated OEM BIOS, meant for integration in motherboard BIOSes. Silicon Image has not released a changelog for this SATA BIOS (they never do).
Here is the new SATA BIOS
Your BIOS sure is chocked full of stuff, 20% of it is taken up by the Asus boot-up image, you have 3 PCI roms, anti-virus, the BIOS flashing tool is actually right in there too......
If you like, I can integrate this SATA BIOS into any official Asus BIOS you want, provided it is in .bin format and not special Asus formats like .afs