When creating custom projectiles, I strongly recommend using move() rather than altering the x & y; it will be much easier on the server, also.
PHP Code:
function onCreated() {
onMovementFinished();
}
function onMovementFinished() {
temp.movex = sin(this.angle) * SPEED_HERE;
temp.movey = cos(this.angle) * SPEED_HERE;
move(movex, movey, .1, 8);
}