How to I add a drive to a system that already has a software raid on it

view story

http://askubuntu.com – I currently have a Ubuntu 12.04 server booting off a USB stick and running a raid 0 configuration with 2x 2TB drives. I would now like to add an additional stand alone drive (not as part of the raid). When I add the drive to the server and reboot I get an error indicating that my raid is degraded. Is this configuration possible with an existing software raid? One more note: the 2 x 2TB drives are 6gb sata drives that show as sata in the bios the new drive is a 1TB drive and it shows as scsi in the bios. Not sure if this matters but I have seen forum post indicating that ide / sata mixes wit (HowTos)