ActionScript 2.0 :: Making Slider Stop In A 'natural' Way?

this may seem like an odd question. well after spending ages getting my slider to act like I want I now want it to stop at a certain point - but to act 'naturally' - basically the slider accelerates the more a button is pressed and uses a set deceleration number to slow down the slider when the button is unclicked. So the faster its going the longer and further the slider takes to slow down - 'ease' down. when it reaches zero it stops.

If you click on the blue arrow in the movie youll see what i mean. The problem comes up when i want to get the slider to stop. I want the slider not to go beyond a certain point (say 600). This gets very difficult if the slider is to act naturally (as before). I guess some kind of reverse engineering is required that works out what point to start the slow down based on where the slider is and what speed its going at??