I'd say you have 2 ways to go about this: 1. Use ASM to create snaps and restore from them. ASM can do snaps of individual VMs or complete CSVs, and also do the necessary things to restore them. Functionality provided for Server 2012 is much better than for 2008R2, BTW. 2. If you need / want to do it manually, this article will help: blogs.msdn.com/.../10169759.aspx  It explains why you need to change the disk signature and how to do it.
I have a new install of a 6110xs and a 3 node 2012 hyper-v cluster.  I have been testing and have not been able to mount a snapshot to any of the servers to copy data off of.  I am able to make the snapshot on the equalogic array, see the snapshot in the iSCSi initiator and I can also see the volume in disk management.  Disk Management sees the volume but it is reserved and I cannot bring it online as it says it is being managed by the Failover Cluster component.  When I go to failover cluster manager it does not see the volume (snapshot). I have found some other posts on this issue but no resolutions. Any help is appreciated. thanks Scott
Unable to Mount Snapshot volume on hyper-v cluster