Trying to Add a Hot Spare to RAID5 on HP 641 Controller

[DavidRoss]

I have a ProLiant ML350 G4p with 4 72.8 GB SCSI in a RAID5 running on a 641 Controller with no hot spare. I picked up another 72.8 GB drive of the same HP model and wanted to add this as a hot spare. I put it in Port 4 and ACU gave me no option of adding it as a spare. I read in ACU's (limited) help files that what seemed to say was I needed to "expand" the array first. So I did. This I believe was a mistake. Now I have two Arrays. RAID5 on 4 drives in Ports 0 - 3 and a RAID0 on the single drive in Port 4. Still no option to set it as a hot spare. I have now deleted the RAID0 but I can not remove the physical drive w/o ACU complaining. I just want to either get back to the original single 4 drive RAID5 OR have this first drive be a hot spare without having to delete everything and rebuild from backup. Can someone tell me the steps I need to take and/or a good source for documentation/manual on how to run/configure RAIDs with the 641 controller? Thank you ahead of time.