Can i set the "My Documents" path to another drive/drives during inst?

Pretty much all said in the title, but I'll flesh it out here anyway.

Basically, am about to build a new system for a friend, Win 7 Ultimate x64, with a 120GB Corsair Force GT SSD for OS and programs, and two 1TB Seagate Baracuda 7200rpm drives in a mirrored array for data/documents.

What I would ideally like to do, is set Ll this up during installation so that opening My Documents automatically paths to the RAID array.

1) If this is possible, how do I do it?
2) If not, how do i make Windows permanently move the my docs path after installation?

Just in case it makes any differance, I will be installing from an upgrade disc, with Windows XP home disc for proof of upgrade.

Take a look here:
User Folders - Change Default Location

User Profile - Change Default Location

Just wanted to say thank you, I used the solution posted by kado and it worked like a charm. First I installed the OS to the ssd, which was the only visible drive, then, when in audit mode, I installed the raid drivers, and set up the system according to the tutorial.

Suffice to say I am now insanely jealous of my friends pc.