[CentOS] installing raid1 via serial terminal during install

Hello,
    I'm wanting to install centos via serial terminal on to a box without 
monitor. It will be administered remotely via ssh. I've got two disks in it 
and would like to use raid1 with this system, but i'd like to get this going 
preferably during or immediately after the install. My problem as i see it 
is installing grub on to both hard disks, you have to get a shell window 
during the install for that otherwise the box won't boot. Does anyone have 
this working?
Thanks.
Dave.