How to get a layer visibility info ?

<?xml version="1.0" encoding="utf-8"?>
<mx:Application
  xmlns:mx="http://www.adobe.com/2006/mxml"
  xmlns:awx="com.esri.aws.awx.*"
  xmlns:map="com.esri.aws.awx.map.*"
  xmlns:layers="com.esri.aws.awx.map.layers.*"
  xmlns:framework="com.esri.aws.osgi.framework.*"
  xmlns:services="com.esri.aws.services.*"
  layout="absolute"  
  >
  <mx:Script>
    <![CDATA[
      import com.esri.aws.awx.map.layers.LayerVisibility;
      import mx.collections.ItemResponder;
      private function onFrameworkStart() : void
      {
        parcels.getLayerVisibilities( new ItemResponder(
          function(data:Object, token:Object = null):void
          {
            for each ( var layerVisibility : LayerVisibility in data )
            {
              trace( layerVisibility.name + " " + layerVisibility.visible);           
            }
          },
          function(info:Object, token:Object = null):void
          {
            trace(info);
          }
        ));        
      }
    ]]>
  </mx:Script>
  <framework:Framework
    apiKey="19640523"
    frameworkStart="onFrameworkStart()"/>
  <map:Map>
    <map:basemaps>
      <layers:VectorGroupLayer id="parcels"
        dataSource="ArcWeb:BR.Parcels.US"
        autoLoadLayerVisibilities="false"/>
    </map:basemaps>
  </map:Map>
</mx:Application>