Them use a bigger rectangle and move the stuff inside
Code:
var tclip:MovieClip = new MovieClip();
var sbmdt:BitmapData = new BitmapData(20,20,true, 0xFF0000FF);
var sbmp:Bitmap = new Bitmap(sbmdt);
tclip.addChild(sbmp);
sbmp.x -= sbmp.width/2;
sbmp.y -= sbmp.height/2;

//container clip
var cclip:MovieClip = new MovieClip();
cclip.addChild(tclip);
tclip.x += tclip.width/2;
tclip.y += tclip.height/2;

var ma:Matrix = new Matrix();
ma.translate((tclip.width/4),(tclip.height/4));

//array of bmdts
var bmdt:Array = new Array();
var bmp:Array = new Array();
var j:int = 0;
var k:int = 0;
for(var i:int = 0; i<=360 ; i++){
	tclip.rotation = i;
	bmdt[i] = new BitmapData((tclip.width + tclip.width/2),(tclip.height + tclip.height/2), true, 0xFFFFFFFF);
	bmdt[i].draw(cclip,ma);	
	bmp[i] = new Bitmap(bmdt[i]);
	
	k++;
	if(k>12){
		k=1;
		j++;
	}
	  
	bmp[i].x = 40*k;
	bmp[i].y = j*40;
	addChild(bmp[i]);
}

var showThis:BitmapData = new BitmapData((tclip.width + tclip.width/2),(tclip.height + tclip.height/2),true, 0xFFFFFFFF);
var showBmp:Bitmap = new Bitmap(showThis);
addChild(showBmp);

var c:int = 0;

addEventListener("enterFrame", oef);
function oef(ev){
	c++;
	if(c > 360){
		c =0;
	}
	showThis.fillRect(showThis.rect, 0x00FFFFFF);
	showThis.draw(bmp[c]);
	showBmp.x = mouseX;
	showBmp.y = mouseY;
}