KB: VM with GPT pass through disk on a Hyper-V cluster with SAS based storage array will cause VM to report “Unsupported Cluster Configuration.”

This issue exists in SCVMM 2008 R2 and will be fixed in SCVMM 2012 for now you can find only workarounds here.

KB: P2V fails with GPT partitions in System Center Virtual Machine Manager

Just released article about VMM 2008 R2. If you have such issue learn how to resolve it here.