Letting users change their expired passwords through RDP when connecting to a Hyper-V Windows 7 Client

We've had a problem at work where users could not log on when their passwords expired. These users are using thin clients (Microsoft Thin PC) and connecting to a server running Server 2008, with Hyper-V installed. Hyper-V is running Virtual PCs with Windows 7 professional as the OS. We require users to change their passwords once a year for security, but they were not even given the option to change their password. 

After many, many, many weeks of searching we did finally find an answer to this. Its a simple registry key that needs changing and for all you lovely people out there, here it is

The location is HKey Local Machine -> System -> CurrentControlSet -> Control -> TerminalServer -> WinStations -> RDP-TCP

The registry key which needs changing to get the VM’s to change expired password is SecurityLayer =0

This should be changed on the Virtual PCs themselves and not the thin clients.

Hope this helps people