Return computer to sleep after backup

My computer will not, for any reason go back to sleep after a backup is run. I'm not looking to 'resolve' this issue by changing the idle timeout of the computer, I'm looking to resolve this by having it sleep after a backup. I upgraded my mainboard / CPU, now my mainboard runs UEFI and sleep mode works with either the supplied script below or when I run Start -> sleep.

Things I've tried:

• I've disabled all startup items
• Closed all programs
• Scoured the internet for an answer and can't seem to find any reason why after the backup the computer shouldn't go back to sleep.
• http://social.technet.microsoft.com/Forums/en/w7itprohardware/thread/2a…
• http://www.vistax64.com/tutorials/171042-sleep-return-timeout-unattende…

But I haven't come up with a viable solution. Any help would be greatly appreciated.

I've ended up configuring a script to run the following: powershell.exe -command "foo.ps1" The contents of which are as follows:

Add-Type -Assembly System.Windows.Forms[System.Windows.Forms.Application]::SetSuspendState("Suspend", $false, $true)

This doesn't work if I want to run a manual backup.

Windows 7 x64bit. ATIH 2012 + Power Pack.