What can you tell me about the host that was restored on the Mirrored side? Is the host name the same? Did they run sysprep?
It sounds to me like SnapDrive on this new host at the mirrored side is managing the original host. There is nothing preventing you from mapping / unmapping LUNs from both systems through the centralized interface.
If your customer does not want to see or manage the other (original) host I’d right-click on the original server name in that left-hand window and disconnect from that server.