When using an external SWF as a MovieSkin, you can't apply the skin until after the external SWF has loaded. Otherwise, the skin will just be blank. The examples in the repository show how/where to use a MovieSkin in the callback invoked after the extrernal SWF is successfully loaded.
The MovieSkin class requires Flash Player 8. It uses the BitmapData class, so it won't work in Flash Player 7.
MovieSkin类需采用Flash Player 8。因为BitmapData类的使用，所以它无法在Flash Player 7中使用。
In Sandy 1.1, you have to provide a movie clip instance to the MovieSkin cons***ctor. Therefore, you have to handle the preloading of an external SWF yourself. You can use the MovieClipLoader class as shown in the ExternalMovieSkin11.as example in the code repository.
In Sandy 1.2, you can provide either a library symbol or an external URL to the MovieSkin cons***ctor. In the latter case, you must also listen for the SkinType.onUpdateEVENT, which is triggered when the external SWF has loaded, as shown in the ExternalMovieSkin12.as example in the code repository. (Sandy 1.2 handles the MovieClipLoader details for you and issues the event when loading is complete.)
The second parameter passed to the MovieSkin cons***ctor determines whether the movie clip will animate. Pass ***e to disable animation (improves performance) and false to enable animation.
通过的MovieSkin构造函数的第二个参数决定是否将动画的影片剪辑。Pass ***e to disable animation (improves performance) and false to enable animation.（这一句不会翻译）
Flash security restrictions apply, so be sure to test with a SWF that is loading from the same domain. Once you figure that out, you can try to get it to work cross-domain using either cross-domain policy files or a proxy server.