Sending URLVariables with FileReference.upload()

I’m attempting to send URLVariables along with my FileReference.upload(). However, my PHP script is not receiving the data I’ve sent along with my URLVariables object. A snippet of my code is below. Any ideas? I appreciate any help in advance.

var fileReference:FileReference = new FileReference();
var request:URLRequest = new URLRequest( “/assets/upload.php” );

var variables:URLVariables = new URLVariables();
variables.file_name = “myFile.jpg”;

request.data = variables;

request.method = URLRequestMethod.POST;

fileReference.upload( request );

You should use an HTTP debugger like HttpWatch, or Fiddler HTTP Debugger to inspect the body of the POST data being sent.

I find that is usually how I find my POST data errors.