powershell commands for VM backups in 2012 vs 2008

I have a powershell routine that is used by task scheduler that will shut down one or more Hyper-v VMs from a list, create a backup of the VHD file(s) then restart the VM(s).  It works great in 2008 but when I copied it over to a 2012 host, it didn't do anything.  I was wondering if powershell commands from 2008 still work in 2012 or if they've been completely rewritten.  If they are the same, then I'll assume "operator error" and keep trying.  If they have changed, then I know that I'll be spending my week googling around for how to use the new commands.  Thanks.