How the hell do I tell the game, that when I put my little throttle lever to a certain position, that my ship flies with that amount of speed?
Pull your throttle all the way down, then go to Options - Controls - Flight Throttle - Throttle Axis - click on the button and push your throttle up, the game should now recognize the axis and you are set.
Also when I put it all the way down, my ship should be at a hold and not go into reverse throttle.
You need to set the throttle up as "forward only" and then use a button on the throttle for reverse, either as "HOLD" or "TOGGLE".