Help setting up raid

Ok i've been trying to set up a raid for a while now but everytime it just doesn't work. Ok here's what'a happening now. I have followed the mb manual to the letter, enabled raid in bios and enabled the raid as a boot device, Then i set up the raid in the raid utility after post. I'm trying to create a raid 0 with 2 200gb disks ok now i go to setup of xp. I press the f6 function to load the drivers, i load the drivers then right after it says setup is starting windows it comes up saying there are no disks attached. I mean the bios see's all three disks i have. the raid utility sees them and lets me pick the 2 i want in the raid. it creates them so why doesn't windows see them? Now previously i was using one samsung200gb disk and one seagate 200gb disk but i thought it must have been cos they're different models and bought the exact same samsung one. Still the exact same problem. I want to ask does anyone think it might be because i hadn't done a FULL format of the disks beforehand. I mean can this really make windows not see them at all? I've been trying this for so long any help will be so gratefully received. mb is asus p5w dh deluxe. Thanks a million. Max.