I really don’t know why they did it but in Server 2012 and Windows 8 Microsoft have decided to make it really difficult to shut down and restart. And if you are in a remote desktop session it’s even harder than when you’re on the console.
Fortunately there’s a handy key-press they haven’t gotten rid of yet, namely good old Alt+F4. Just click on an empty space on the desktop, give that particular two-fingered salute and you get the following dialog:
So there we go. To be honest I was surprised it worked in an RDP session – I fully expected my session to get killed instead, but no it does indeed work as it needs to.