Let me try a simpler explanation.
The greater the angle of attack, the greater the lift. Lift increases because the distance the air must flow along the upper camber increases. As this angle changes, the point where the airflow is fastest (lowest pressure/separation point) moves forward relative to the total distance the air must flow, therefore, so moves the centre of pressure (lift).
If you want the really long version, I'm happy to help.
Last edited by PappyJ; 13th May 2013 at 18:39.