Sending metaData with netStream.send is not working

I'm trying to send metaData from client to FMS server when recording Webcam video and have implemented sending of metaData as stated on Adobe's help page at: http://help.adobe.com/en_US/FlashMediaServer/3.5_Deving/WS5b3ccc516d4fbf351e63e3d11a0773d56e-7ff6.html

However when I play the recorded video  from FMS, my custom metaData properties trace "undefined". I can trace  default metaData properties such as duration or videocodecid  successfully, but not my custom properties such customProp, width or height. Here is part of my code that is related to the issue:
 
private function  ncNetStatus(event:NetStatusEvent):void {              
     if  (event.info.code == "NetConnection.Connect.Success") {   
          ns = new NetStream(nc); 
         ns.client = this; 
          ns.publish(webcam_test, "record");   
     }   
}
 
private function netStatus(event:NetStatusEvent):void {  
     if  (event.info.code == "NetStream.Publish.Start") {  
          sendMetadata();     
     }
}
 
private function sendMetadata():void {
      trace("sendMetaData() called...");
     myMetadata = new  Object(); 
     myMetadata.customProp = "Welcome to the Live feed of  YOUR LIFE"; 
     ns.send("@setDataFrame", "onMetaData",  myMetadata);
}
 
public function  onMetaData(info:Object):void { 
     trace('videocodecid:  ',info.videocodecid); //returns 2
     trace('customProp:  ',info.customProp); // returns undefined
}
 
And here is my trace result:  
NetConnection.Connect.Success
NetStream.Publish.Start
sendMetaData() called...
NetStream.Record.Start
Stopped webcam recording... 
NetStream.Record.Stop
NetStream.Unpublish.Success
NetStream.Play.Reset
NetStream.Play.Start
videocodecid: 2 
customProp: undefined