Разместите анимацыю на сцене и задайте ей
Instance Name [animation]

Код AS3:
import flash.events.Event;
import flash.display.MovieClip;
var targetTime:Date = new Date(
2012, // год
4, // месяц [0..11]
9, // день [1..31]
18, // час [0..23]
0, // минуты [0..59]
0, // секунды [0..59]
0 // милисекунды [0..999]
);
var mc:MovieClip = this.getChildByName("animation") as MovieClip;
mc.visible = false;
mc.stop();
this.addEventListener(Event.ENTER_FRAME, handleEnterFrame);
function handleEnterFrame(event:Event):void {
var current:Date = new Date();
if (current < targetTime) return;
this.removeEventListener(Event.ENTER_FRAME, handleEnterFrame);
trace(current, "<", targetTime, "=", (current < targetTime));
mc.visible = true;
mc.gotoAndPlay(1);
}