Mirror LCD-Display to external Monitor

[Altermac]

I'm looking for a Way to mirror the content of the internal LCD-Display to an external Monitor oder Beamer. The AAO should use external VGA-devices with 800x600, 1280x1024 or preferred 1024x768. I don't want to extend the Desktop to a second Display, because I want to use the AAO in Front of an Audience. Using fn-Keys to switch Displays would be fine. I'm using Linpus on my AAO.

Has anybody done that?

 

[Zero]

"oder beamer" should be "or projector", I suppose. (German?)

Does Fn + F5 not work?
I haven't tried it, but I am also interested, because I need that function for lectures.

 

[Altermac]

xrandr knows the external Monitor, but switching to external VGA does not work.
FN-F5 sets back to normal (only 1024x600) wich does not show on external 4:3-VGA-LCD/Monitor.