Can someone help me?

mm i like cherries! well anyways, for the car component thing in the flash mx game control. is there anyway to have specific borders? like instead of putting the numbers for the borders, can u just put a movie clip and have a instance name for where the car cannot go pass?
http://www.kirupa.com/developer/mx/gamecontrols.htm = car thing is here!

oh and by the way, heres some code and i wanted to know how to make a down button so when u press | , then the car would go backwards. V

onClipEvent(load){
control_coche = 0
colision = 0
velocidad = 8
}
onClipEvent(enterFrame){
if (Key.isDown(Key.ENTER) && !lock){
control_coche = 1
_root.empezar._visible=0
}

if( control_coche == 1){
if (Key.isDown(49)) { velocidad = 1; _root.velocidad.gotoAndStop(1)}
if (Key.isDown(50)) { velocidad = 1.5; _root.velocidad.gotoAndStop(2)}
if (Key.isDown(51)) { velocidad = 2; _root.velocidad.gotoAndStop(3)}
if (Key.isDown(Key.UP)) { acelerar = velocidad }
if (Key.isDown(Key.RIGHT)) { _rotation += 5 }
if (Key.isDown(Key.LEFT)) { _rotation -= 5 }
_y += acelerar * Math.sin(_rotation/57.3)
_x += acelerar * Math.cos(_rotation/57.3)
acelerar *= 0.8
}
//checar si se gana
if (this.hitTest(_root.premeta)) {
preparar_ganar = 1
}
if (this.hitTest(_root.meta) and preparar_ganar == 1) {
_root.ganar._visible = 1
_root.otravez._visible = 1
for (i=1 ; i<=6; i++ ) {
set ("/" add Number (i) add “:control_coche”, 0)
}
}

if( colision == 0){
//colision contra coches
for(i=1; i<=6; i++){
if (this.hitTest("/“add Number(i)) and _name <> i ){
this.gotoAndPlay(2)
colision = 1
control_coche = 0
_root.otravez._visible = 1
_root.perder._visible = 1
lock = true
}
}
//colision contra paredes
for(i=1 ; i<=7; i++){
if (this.hitTest(”/pared"add Number(i))){
this.gotoAndPlay(2)
control_coche = 0
colision = 1
_root.otravez._visible = 1
_root.perder._visible = 1
lock = true
}
}
}
}