Laptop Projector problems

I have a Compaq Armada 7400 and a IBM Think pad I have to set them up to use an InFocus LitePro 220 projector. When I use the IBM with a docking station it works just fine, but when I use the IBM by itself and I use the projector I can not get the display on the projector and the laptop, and when I use the key combination to use the projector the IBM display goes black and I cannot get the display back. I need to get the display to be on the projector and the laptop screens.
The Compaq mostly works but on the display it is not the complte desktop are. If you move the cursor to the edge of the display it shifts over to show more of the desktop. What is the trick to using a laptop and the projector
Dennis