Dual boot with vista, But XP cannot see SATA drives

This is a great guide but i keep getting stuck when trying to install XP. I have 2x Segate 320GIG SATA 300mbs drives . One is partitioned in two equal parts C: & D: one already has vista on the waiting for xp. The other just a storage drive.
On getting to the XP install it just can not see the any of the drives. Have tried loading the correct drivers, they are not 'RAID' just SATA used on thier own, during installation but just no luck.

HELP!!! been trying for ages now.