Hyper-V and iSCSI drive. Change the driver letter.

Hi again
I have a hyper-v server with 3 drives for the VM.
the first drive is a Raid 5 local drive.
the second and third drives are in a EMC iSCSI SAN.
I have 5 VM in the second drive.
I need to change the letter to this driver (Don't ask me why, It is too long to explain ;-) )
I change the path letter in the VM options. For the snapshots and for the .vhd file.
I tryed to run the machine.
I failed .

I did waste time to study the error.
So I moved the VM with the VMM08 and I changed the drive letter from V: to U:

Santos