Windows Software Raid - Boot from Mirror HDD

Hi, I have an old Windows 2003 R2 server with two HDD's. One HDD is used as the boot drive holding the windows system files. The other HDD is a data drive with many shared folders.. The primary drive has developed a mechanical  fault and fails to boot on most occasions. I connected a third HDD with the intention of creating a software mirror as hardware Raid is not available. I eventually managed to boot up the Faulty HDD and created a software mirror on to the newly installed HDD through the Windows Server 2003 Disk Management utility. Once complete I powered the system down.

I now want to disconnect the faulty HDD and boot the system from the mirror HDD. It appears it not as simple as that. I looked at the boot.ini file and added a line to reflect the mirror HDD as a boot option.

[boot loader]
 timeout=30
 default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
 [operating systems]
 multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Windows Server 2003, Standard" /noexecute=optout /fastdetect

 multi(0)disk(0)rdisk(1)partition(1)\WINDOWS="Boot Mirror C: - secondary plex"

Doesn't seem to work though. Without the original boot HDD the system fails to find an OS. Can anyone shed some light on this and help me figure out how to boot from the mirror? Does the faulty drive need to remain connected?

Regards, Aelara.