Cast loaded SWF with designed interface in main class - actionscript-3

Question

First of all I read linked topic but unfortunately any of the tips didn't work for me: Casting a loaded SWF as an interface
My problem indeed is similiar, I have got created SWF (Content.swf) where Content.as which is document class there:
package {
import flash.display.MovieClip;
public class Content extends MovieClip implements IGame {
public function igameMethod():void {
trace("implemented method of IGame");
}
}
}
IGame interface (in the same directory as Content.as) contains sole method 'igameMethod'
package {
public interface IGame {
function igameMethod():void;
}
}
and such compiled SWF is loaded by Loader class in LoadSWF where Main.as is document class and it is something like that:
public class Main extends MovieClip {
private var swfLdr:Loader;
private var game:IGame;
public function Main():void {
if (stage) init(); else addEventListener(Event.ADDED_TO_STAGE, init);
}
private function init(e:Event = null):void {
removeEventListener(Event.ADDED_TO_STAGE, init);
swfLdr = new Loader();
var r:URLRequest = new URLRequest("../lib/Content.swf");
var defaultLoaderContext:LoaderContext = new LoaderContext(true, ApplicationDomain.currentDomain);
//none of settings for ApplicationDomain doesnt' work (with checkPolicy or with or without ApplicationDomain.currentDomain set)
swfLdr.load(r,defaultLoaderContext);
this.addChild(swfLdr);
swfLdr.contentLoaderInfo.addEventListener(Event.COMPLETE, onExternalSWFLoaded);
//tried Event.INIT too without success
}
private function onExternalSWFLoaded(e:Event) : void {
var Game:Class = ApplicationDomain.currentDomain.getDefinition( "IGame" ) as Class;
if (e.target.content is IGame) {
trace("Is IGame");
}else {
//output of this condition is false
//so e.target.content is not IGame
trace("No its not IGame");
}
var Game:Class = ApplicationDomain.currentDomain.getDefinition( "IGame" ) as Class;
//tried to cast as class without success too
var gameContent: IGame = IGame(swfLdr.content); //app breaks here
// TypeError: Error #1034: Type Coercion failed: cannot convert LoaderSWF#87f0089 to IGame
}
I've got also IGame interace (duplicated to LoadSWF project) with the same package structure (in the same folder as document class) as Main.as to let LoadSWF use igameMethod() on Content.swf, but i can not use it because of TypeError: Error #1034: Type Coercion failed: cannot convert LoaderSWF#87f0089 to IGame. So the compiler can't convert this Content to IGame.
Have you got any idea, which would help me with this topic?
Thanks for any tips in advance.
Kindest regards Pawel