We had to work out how to do this for our XPe Devices. It took my collegue a long time to work out the way to solve this issue, but Jean Marc managed in the end.
We have decided to write it down on my blog, so please see
How to stop an Admin account getting Local GP settings | Simon Todd's Free Technical Blog!
The post tells you which keys to change to stop local GP settings being forced on a local admin
Thanks