i just did this yesterday cuz i reformated.
make sure RAID is enabled in your bios.
reformat your HD and delete all partitions
reboot, there should be a screen like F10 to enter RAID configureation, if you activated RAID in your BIOS right after the first screen. (i am not sure if this is nessisary, but i did it and i'm running RAID now soo.... it must not hurt anything
make sure that the storage devices are on one array...
reboot from windows cd.
one of the first things it says on the bottom when the blue reinstall screen comes up is something like "Hit F6 (?) to install 3rd party RAID or SCSI drivers" or somethign like that.... hit the button.
put the 3.5" floppy w/ RAID drivers in the drive, install them. (it will say something like to install such and such hit enter, do it, pick one of the 2 drivers, then do it again to install the 2nd one)
exit that part of the install and the normal windows install should start up again.
you will know you did it right if there is just one big 72GB drive (148GB in my case) in the 'unpartitioned space' when it asks you where to install windows.