Vista - Failover Guest Cluster -- 'The process cannot access the file becauseit is being used by another process.'

Hello,

I have setup a failover cluster using Hyper-V vms. Both guests are
Windows Server 2003 Enterprise 64-bit systems with SP2. The host is
Windows Server 2008 Enterprise 64-bit, full installation. I have
separate volumes for the guest OS and swap. These are on the default
IDE controller. The cluster volumes are on the SCSI controller. All
guest volumes are offline disks because I am using the pass-thru.

I am confident of the guest cluster configuration. When I V2P it out
onto hardware and use the same disks, the cluster starts properly.
When I P2V the cluster nodes into Hyper-V, the cluster will not work.
When I map the guests to the same disks, which is a requirement of
failover clustering, only one guest can boot. The error on the second
guest is:

'Node2' failed to start.
Microsoft Synthetic SCSI Controller
Failed to power on with Error 'The process cannot access the file
because it is being used by another process.'

What additional configuration changes are needed to allow one offline
disk to be shared by two Hyper-V guests?

J Wolfgang Goerlich