no bootdisk is needed. just make sure in the directory of the kernels of the first install cd you have sata.i together with the others. when you boot from the cd type sata.i for choosing a kernel although itīs not in the list.
the hard disks will be hda, hdb,...
after that get a 2.6 kernel, compile it for sata support, change your fstab file by replacing h with s for the hard disks
hda1 -> sda1 and so on
slack-current has sata.i in the 1st cd
thatīs how i did it
KISS - keep it simple stupid
deiba maa mu i slack
edit: btw i have 2 sata seagate 80gb, no raid though