During the Ubuntu 12 install, I get the a screen that says "ATA RAID Device Detected" and asks if I want to enable it. Having used Lenovo Easy Setup to configure the raid (1 array with 2 1tb drives) I chose "Yes".

It takes me to the Partition manager where I can see three options, and a blank line after the first:

* Configure iSCSI

* ___________________

* Undo Partition Changes

* Write changes to disk

I have no idea what iSCSI is but I'm pretty sure it's not for me.
Undo partition changes just hangs the system at a purple screen.
Write changes to disk gives me an error stating no root files system is defined.

What should I do to get Ubuntu installed with the RAID?