Hibernating a guest VM on Hyper-V

Hi,

I need to hibernate a VM to use some automated tests. My VMs are running Server 2012, and my host is Windows 8, with Hyper-V. Apparently this was possible in 2006 (http://blogs.msdn.com/b/virtual_pc_guy/archive/2006/01/23/516119.aspx) however I can't figure out how to make it work with my current set-up, I simply get "the system firmware does not support hibernation" when I try to run "powercfg -h on" (on the VM of course).

Does anyone know if this is possible and how to do it?

Thanks, Adrian