While I am #software #dev saavy, am not a #ui / #ux pro.
But to my mind if you have a control, that one might normally expect to see somewhere, that can be disabled by some global or scoped restriction or in this case a #Windows #domain/group #policy... DONT HIDE THE FUCKING THING.
Show the button in the same place, but disabled. And if you mouse over if it says "Disabled by <setting>" or "Restricted by group policy <name of policy>".