Load movie container isue

programming flash
1

Hello I have a few questions. This is how I made a container for an extrnal movie clip :
this.createEmptyMovieClip(“mc_1”,0);
mc_1.createEmptyMovieClip(“container_mc”,99);
mc_1.container_mc._y = 300;
mc_1.container_mc._x = 0;
//mc_1.container_mc._width = 746;
//mc_1.container_mc._height = 500;
var n:MovieClipLoader = new MovieClipLoader();
n.loadClip(“brokers.swf”,mc_1.container_mc);

Ok now what I want to do is to load the movie in the container, and only be 746/500 …and only that part visible. What am I doing wrong ?
This doesn’t work " mc_1.container_mc._width = 746; "

               Thanks