[MX2]Change the size in action script

1

Here is what I have. I made a box that is 3x3px and it fades in, now I want it to change size from 3x3 to 300x300px. Now how would this be done? here is my code so far:


// create the box
	_root.createEmptyMovieClip("Box", 100);
	//starting alpha
	Box._alpha = 0;
//box
	_root["Box"].lineStyle(2, 0x2D3E34, 100);
	_root["Box"].beginFill(0xA2BBAD, 100);			
		_root["Box"]._x=5;
		_root["Box"]._y=5;
		_root["Box"].moveTo(0, 0);
		_root["Box"].lineTo(3, 0);
		_root["Box"].lineTo(3, 3);
		_root["Box"].lineTo(0, 3);
		_root["Box"].endFill(0, 0);

//change alpha
	speed = 5
	Box.onEnterFrame = function ()
	{
		if (this._alpha < 100){
			this._alpha += speed;}
		else{
			delete this.onEnterFrame;}
	}

I want the box to change size while it is fading in.
So fare I’ve tried scale and width but those change the border size too, which is really annoying because I end up with a 100px border and a 100px box, not exactly what I was going for.