Dynamically inserting XML

Question

I am trying to append onto a xml object dynamically.  The format of the XML is as follows
<Graph>
     <Line name="---">
          <point x="---" y="---" />
          <point x="---" y="---" />
     </Line>
     <Line name="---">
     </Line>
</Graph>

Answer 1

Here is my current code:
    public function appendToLine( strName:String, aXPoints:Array, aYPoints:Array ){
        //find the line in the xmlGraph
        var appendPath:String = "myGraph.firstChild";
        for(var currPoint:XMLNode = myGraph.firstChild; currPoint != null; currPoint = currPoint.nextSibling)
          //traverse through the lines til you find the match
            if( "Line_"+currPoint.attributes.name == strName ){
                //appendPath is the location of the line that needs to be appended onto
                break;
            else{
                appendPath = appendPath + ".nextSibling";
        trace("Append Path: " + appendPath);
        //append XML now has the node of the current line.
        for( var i:Number = 0; i < aXPoints.length; i++ ){
            // draw the line
            this[strName].lineTo( aXPoints[i]/70 * 640, 480-aYPoints[i]/20000*480 );
           //create xml to append
            var xmlTemp:XML = new XML();
            xmlTemp.parseXML("<Point />");
            var temp:XMLNode = xmlTemp.firstChild;
            temp.attributes.x = aXPoints[i];
            temp.attributes.y = aYPoints[i];
            //append
            this[appendPath].appendChild(xmlTemp);//not working
            trace(appendPath);
            //testing appendChild();
            myGraph.firstChild.appendChild(xmlTemp);
            trace("=-=-=-=-=-=-=-=-=-=");
            trace(" ");
            trace(myGraph);