Having a somewhat similar problem, I used modprobe to load the pata_amd and amd74xx modules, when my IDE drives weren't seen. Next fdisk -l command they were then present. The problem seems to be between hardware detection and choosing which controller modules to load. When the correct modules are loaded, the drives can be seen.
Interesting. I've also encountered this problem recently, with four SATA drives attached to an Asus A8V-MX motherboard; performing the usual due diligence of a forum search lead me to this thread, where I've accordingly endeavoured to follow your advice above. I found basically similar results; live CD boots successfully but the SATA drives are not 'seen' - however, none of the modprobe efforts were successful at all... modprobe -l | grep sata did return a list of SATA modules, yet inserting each in turn failed to produce any fdisk -l detection results.,
The reason I am posting in this thread now is because today I stumbled upon a possible solution:
http://mylinuxramblings.wordpress.com/2010/02/04/linux-hell-via-southbridge-vt8251-sata-ii-controller/Rebooting, and passing the "pci=nomsi" boot parameter to the kernel via GRUB did produce immediate results - all four SATA drives were then detected, and I was able to partition and format them successfully. As they seem to be alright now, I shall next attempt to continue with the install.
Regards, and good luck to all with motherboards having VT8251 southbridge chips!