Advice about setting up Microsoft Cluster using VM's

We are currently trying to virtualize a physical 2 node Microsoft Cluster (Win2K3).

We have set up the production network and heartbeat network- and this works fine

We have existing shared storage (SAN) which is connected to the physical cluster and we have presented the same storage to our ESX hosts as raw LUNs.

The shared disks have not been formatted to VMFS

Is there a way to migrate the physical Cluster to VIrtual without any outage on the Cluster?

Thanks