Json Post raw data from FLEX

I want to post raw data using FLEX and JSON (and get the result in PHP). I succeed to store my JSON data into an object and post object as HTTPService.send expects. But it isn't a post raw data.

// my ActionScript code

                var objSend:Object = new Object();
                updatedObj.id = "myid"
                updatedObj.action = "mydata";

                objSend.jsonSendData = JSON.encode(data);
                myHttpService.send(objSend);

// my HTTPService

<mx:HTTPService id="myHttpService" url="myurl"
                    useProxy="false" method="POST" resultFormat="text" 
                    fault="faultHandler(event)">
    </mx:HTTPService>

What I need to do is to post raw data without using an object neither a jsonSendData parameter. My need is to get raw 开发者_Go百科data in PHP just using file_get_contents("php://input"). Thanks a lot.