soccer Game logic for elevation

Can anybody explain the logic behind the elevation of the ball in following link.
http://www.myplayyard.com/play/6872/free-kick-specialist-3
As far as I have understood the game ,the first selection(ie angle) makes the shadow move in that direction and the second selection (ie,elevation) makes the ball move in the projectile motion along given elevation.but I dont understand how to make the ball move in projectile motion with coordinate system being changed to certain angle?Correct me if I have understood something wrong else please help me find the correct solution for the game logic?
How to make a projectile movement for that game ? [import]uid: 45566 topic_id: 33318 reply_id: 333318[/import]