Hi ulf,
When I first started trying to get multiplayer to work with 3DGS long ago, I was doing things similar to what you are trying. I still believe client-side movement is the most effiecent and best way to go. The concept you are using is pretty much the same, the technique was a bit different though. I sent force-over-time and updated actual position every once and a while, while you are sending points to go to, and sending position updates sometimes. With a point-and-click movement game, sending points to go to might actually be more efficient, although with a FPS or real time movement game where the player can change his direction at any time, I think the force-over-time method would have to be used.
Anyway, nice work. Good reading.
Later,
Loco