RAID 0 setup question

[Jackpine]

Although I have studied my Asus P5LD2 Deluxe motherboard manual, I am not sure how to configure my two data drives as RAID 0. This is what I have done so far:

WD 250MB SATA2 installed on SATA1 (red). IDE Configuration set to Standard IDE. Windows XP loaded onto that drive. Windows XP runs fine.

Now, I want to install 2 WD 250GB SATA2 drives and configure them as RAID 0. I am thinking that I plug them into the SATA3 and SATA4 (black) connectors. According to the mobo manual, I have to change the IDE configuration in BIOS to Configure SATA as RAID before I can set up the RAID 0 using the Intel Matrix Storage Manager Option ROM Utility.

But if I do that, what happens to the Standard IDE setting I had previously for my boot drive? Won't that change?

I really need some guidance here because I am at a loss on how to do this.