And again some news...
Now working with the mouse_force values ... and what should I say - It's working fine.

The point that is unsolved by now is about how to display some lines from my pointer-entity along the axis to better being able to estimate the position of the pointer in the 3D-scene.

Again I point out to the built-in (?) function when pressing d while running a level from WED. There are red lines showing along the room borders. How did they make it there? Would be interesting to know.

Greetings