Mouvement physics issue!

Greettings blender heads!
I’m having troubles setting up a ‘mouve inside moving vehicle’ scritp!
First, I tried to use a getLinearVelocity(movingObject) and the own.setLinearVelocity(movingObject), then get the moving object orientation and add apply it to the player or item, supposed to be inside the ship. A near sensor detects if objects are ‘inside’ the ship.
It works to a certain extent. Till the ship reaches certain speed. It seems to me that the sensor is too slow, but also, the player cannot move arround!
I might need to revise some basic physics lessons on movement and relative speed!
So maybe I’ll have to set a local (player) speed which sloud be 0, then add that to the global speed(vehicle’s)… Arrgh I’m ashamed of me self, can some one help me?

Edit: Sorry, I posted in the wrong sub-forum, can a mod move it to the right place?