Cloning to a mirrored drive - "Copy MBR" option Greyed Out

Hello, I am attempting to clone my boot drive (not a mirror - disk 1) to a newly created mirror drive (disks 2 and 3) in Windows 7 with Norton Ghost 15.  My goal is to replace my current boot drive (disk 1) with the newly created mirror drive (disks 2 and 3), so that I can boot from the mirror drive (disks 2 and 3) and eliminate my current boot drive (disk 1). However, when attempting to clone my current boot drive (disk 1) to the mirror drive (disks 2 and 3), and when I get to the "Advanced Options" screen of the Copy Drive Wizard, several options are greyed out, including "Set drive active (for booting OS)" and "Copy MBR".  I understand that both of these options are required to make the destination mirror drive bootable.  Any ideas why such options would be greyed out or how to make them active?  I am wondering if Norton Ghost 15 just does not allow you to make a mirror drive bootable.  Any help is appreciated.

Thank you.