Retrieving http post in c# and asp.net

Question

Yahoo store has the option of recieving realtime orders using http post in xml format. Yahoo has the ability to call a page on our webserver along with the xml data in http post. I created the following code to try and retrieve the post, but when I Response.Write the output it is blank.

Page.Response.ContentType = "text/xml";
// Read XML posted via HTTP
StreamReader reader = new StreamReader(Page.Request.InputStream);
String xmlData = reader.ReadToEnd().ToString();

Does anyone know of another method to retrieve the xml in http post using asp.net and c#. Thanks in advance.