This looks like VMware KB: Physical drive failure on a storage array .
It sounds like nothing here (VMware KB: vSphere handling of LUNs detected as snapshot LUNs ) will work since you can't list the volumes.
Maybe a bit much, but for what it's worth, can you put a 4GB USB stick on the host, and install a fresh copy of ESXi 5.1, and see if you can see the volume with that? That way you don't have to modify any existing configs, other than perhaps the boot order. Sort of like adding a non booting OS drive as a secondary on a working system. Just a couple thoughts..never seen this one myself before.
-Brian