Windows 8 in a VM on 2008 R2 Hyper-V

Update:  As of October 9, 2012, the update has been superseded by 2744129. Go to http://support.microsoft.com/kb/2744129 to find that update, where it states the supersedence in the documentation.

This is an interesting patch that someone recently pointed me to:  http://support.microsoft.com/kb/2526776
Apply this patch to your Server 2008 R2 Hyper-V Server so that you can install Windows 8 in a VM.
If you do not apply this patch and you attempt to run Windows 8 within a VM: note the symptoms in the KB article:

• The Windows Developer Preview or Windows Server Developer Preview virtual machine stops responding.
• The Windows Server 2008 R2 host computer displays a stop error message and restarts automatically. This behavior brings down all other running virtual machines together with the host computer.

That does not sound good.
So, if you have a Hyper-V server that suddenly crashes and reboots, and you know that someone has downloaded the Windows 8 beta and might be installing it into a VM…  Well, you suddenly have an idea what might be going on.