Difference in Flash CS3 AND Flash CS5 Linkage option?

Well, I have Flash file which has one movie-clip (Box1) and it is exported for Action-Script in Linkage option but export for Frame 1 option is unchecked. Now my document Class is here

package  {

import flash.display.MovieClip;
public class GetTimeLineObjects extends MovieClip {

    public function GetTimeLineObjects() {

        var boxObj:MovieClip = new Box1();
        addChild(boxObj)
        boxObj.x=200;       
       }
   }
}

box1 is the movieClip which is exported for Action-Script but it is not exported at Frame1. Now my question is in Flash CS5, Box1 is added to stage and shown on stage even it is not exported at Fram开发者_Go百科e1 while in Flash CS3, the code executes, gives no error but object(box1) is not shown on stage? I think all those objects which are created using code are exported at Frame1 in FlashCS5, no matter you uncheck the option to export at Frame1, the class code overrides the setting of Export at Frame-1? Am i right??

As no-one knows about this mystery so we can assume that in Flash-CS5 export for frame 1 is optional means even it is unchecked, objects or movie-clips are exported at frame 1 when created in Document Class. kindly comment on it. I have checked it using SwiX tool. The Movie-Clips are loaded before even they are not exported at Frame 1 but are created in Document Class using new operator.