I am not familiarized with OVM either, but pretty much is like VMware, but made by Oracle. Of course, hardware and system requirements are different.
But the heart beat is just a simple NIC on the VM that uses a private IP. Why they can't setup that on OVM? Do they really setup the MS Cluster for you or maybe the got confused and setup two independent machines? Ask that.
Again, I am not familiarized with OVM but it should support several NICs on the guest machine.
The only tricky part would be recreating the SAN. That's relatively easy on VMware, but not sure if that may be a problem with OVM. The MS Cluster needs a share disk, and without that, it can't be completed.