Begin December 2012 HP announced that HP Cluster Extension (CLX/3PAR 3.00.00) will support Windows Server 2012.
The sofware also supports Failover capabilities for Windows Server 2012 Clustered Shared Volume (CSV) disks.
See the quick specs document here.
HP Cluster Extension (CLX) software offers protection against system downtime from fault, failure, and disasters. It enables flawless integration of the remote mirroring capabilities of HP Continuous Access or Remote Copy with the high-availability capabilities provided by clustering software in Windows. This extended-distance solution allows for more robust disaster recovery topologies as well as automatic failover, failback, and redirection of mirrored pairs for a true disaster tolerant solution.
CLX provides efficiency that preserves operations and delivers investment protection. The CLX solution monitors and recovers disk- pair synchronization on an application or VM level and offloads data replication tasks from the host. CLX automates the time-consuming, labor-intensive processes required to verify the status of the storage as well as the server cluster, thus allowing the correct failover and failback decisions to be made to reduce downtime. HP Cluster Extension offers protection against application downtime from fault, failure, and disasters by extending a local cluster between data centers over large geographical distances.
I found none other technical information on the Cluster Extension software support for Windows Server 2012 Hyper-V using cluster shared volumes. I guess this is a matter of time.