flex PHPに値を渡して結果をflexで出力

1. <?xml version="1.0" encoding="utf-8"?>
2. <s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
3.       xmlns:s="library://ns.adobe.com/flex/spark"
4.       xmlns:mx="library://ns.adobe.com/flex/mx"
5.       creationComplete="getPhpFile()">
6.   <fx:Script>
7.     <![CDATA[
8.       private function getPhpFile():void
9.       {
10.         var variables:URLVariables = new URLVariables();
11.         var loader:URLLoader = new URLLoader(request);
12.         
13.         // PHPへPOST送信を指定
14.         var request:URLRequest = new URLRequest("anounce.php");
15.         request.method = URLRequestMethod.POST;
16.         
17.         // PHPに送る内容：関数名と引数
18.         variables.function_name = "test";
19.         variables.argument = "reCatNap";
20.         
21.         request.data = variables;
22.         
23.         // PHPを実行
24.         loader.addEventListener(Event.COMPLETE, onComplete);
25.         loader.load(request);
26.       }
27.       
28.       private function onComplete (event:Event):void
29.       {
30.         // 戻り値を変数に格納
31.         var vars:URLVariables = new URLVariables(event.target.data);
32.         trace( vars.comp );
33.       }
34.       
35.     ]]>
36.   </fx:Script>
37.   
38.   <fx:Declarations>
39.     <!– Place non-visual elements (e.g., services, value objects) here –>
40.   </fx:Declarations>
41.   
42. </s:Application>

PHPファイル（anounce.php）

1. <?php
2.   $function = $_POST['function_name'];
3.   if ( function_exists($function) )
4.   {
5.     // 関数が存在するなら実行
6.     $function($_POST['argument']);
7.   }
8.   
9.   function test($name)
10.   {
11.     echo "comp={$name}";
12.   }
13. ?>

実行結果・出力内容？
reCatNap