Drive Mirroring

I am using Novell 4.11 on a Compaq Prosigna 200 server. I want to add an IDE disk and set up a duplex/mirror on the server. I attached the second drive to the secondary onboard IED controller but when I go to install it shows both drives but won’t let me mirror them. When I check the mirror it shows “not mirrored” but when I look at each drive it shows “In Sync”. What am I doing wrong?