Извращение...
Код:
class MyClass {
private var __mc:MovieClip;
public function myFunction(mc:MovieClip){
__mc = mc; // #1
__mc = mc.attachMovie("blah","blah",1234); // #2
__mc = mc.createEmptyMovieClip("blah",1234); // #3
__mc = mc.createEmptyMovieClip("blah",1234).attachMovie("blah","blah",1234); // #4
}
}