Usa setters y getters.
Código actionscript:
Ver originalclass{
public class test{
private var _variableglobal:int = 4;
public function test() {
}
public function set variableglobal(value:int):void
{
_variableglobal = value;
}
public function get variableglobal():int
{
return _variableglobal;
}
}
}