I had that problem with the beta, had to do something in Windows to the drive before it would show (as i was installing it onto my second internal), and i also had to set it to ACHI in the BIOS before it would let me install on it, but i can't remember what it was now, ill have a think and get back.
EDIT: I remember now, i had to go into the Disk Manangement (of me XP), and set the drive to Dynamic/Basic (or something like that) before it would show up, then before i booted up from the disc, i had to change the onboard IDE/SATA Controller mode from IDE to ACHI in my BIOS, as when i tried with it set to IDE still, it said something about not being able to install it on it,
hth