WSS2008R2 - Moving LUNs to another server

• Remove the virtual disk from the iSCSI target with Server Manager. The actual VHD is not touched.
• On Server A, using Disk Manager, I see that the iSCSI target disk is gone.
• Now, if I add the virtual disk back to the iSCSI target, it also reappears on Server A.
• Back on Server A, using Disk Manager, my only choice to get rid of this disk is to make it offline. I can't delete it.
• Using Diskpart.exe, with these commands, I get

select disk 5

Disk 5 is now the selected disk.

delete disk

The disk you specified cannot be deleted.
Please select an empty missing disk to delete.