Hoping this will save somebody else the (literally) hours it took me trying to track this down.
I’d been very frustrated using Remote Desktop Connection ever since I got my Lenovo Twist in the fall because it was missing the Pause and Break keys. So if I wanted to go from full screen RDC back to the windows on my PC, I had to use the mouse to resize the remote desktop.
I tried all kinds of things, including Microsoft’s key mapper, KeyTweak, and SharpKeys. Nothing seemed to work…the Break key seemed to be disabled on this box, probably in the registry. I poked around in the registry looking for a way to re-map it.
Finally I came across this post on the Lenovo blog. It pointed out that break was mapped to Fn+P. So now I can Ctrl+Alt+Fn+P to toggle between full screen and not in remote desktop connection. Awesome. Total victory. Even if I don’t get anything else done today, this is a good day.