VHD Boot, Bcdedit /copy {current} /d "Test"

I have a Win7 (Build 7000) installation and would like to use the VHD-Boot feature to boot into a Windows Vista (x64) installation. I have therefore prepared a Windows Vista VHD with my HyperV Server and generalised it. I used the following commands to add the VHD to my Boot menu:

bcdedit /copy {current} /d "Test"
bcdedit /set {ID from the copy} device vhd=[c:]vmfsvistadisk01.vhd
bcdedit /set {ID from the copy} osdevice vhd=[c:]vmfsvistadisk01.vhd
bcdedit /set {ID from the copy} detecthal on

After rebooting and selecting the new entry I just get a error message (after the attempt to repair something) from Windows 7 (!). I have also tried to create a vista vhd using the win7 waik und imagex - same result. how I can get this running?