I used SuperDuper to clone the original drive to external, then I added the new "GUID drive" (which was external) to bay 1 internal with an identical sized drive in bay 2 to set up RAID 1 mirroring. It won't let me me drag the volumes to create a raid at all. I even tried booting from the OLD internal (in the external drive) to set up raid as well as tried the boot up disc to set it up. I can't lose the data on the Original main disc, but I can swipe the either new 400gb drives and put the data back on. Any suggestions or something I missed on this? thanks in advance!