Can I using cross-site XmlHttpRequest in Itunes LP environment?

Question

Itunes is based on Webkit platform and we can't use cross-site XmlHttpRequest in JavaScript because of security policy. But, as a exception, we can do that with a special header. Here is source code and I did it successfully in Safari:

var url = 'http://mysite.net/canvas.php';   

var mybody = "<?xml version='1.0' charset='utf-8'?><person><name>Arun</name></person>";
var http = new XMLHttpRequest();

http.open("POST", url, true);   
http.setRequestHeader("X-PINGOTHER", "pingpong");
http.setRequestHeader('Content-Type', 'application/xml');

http.setRequestHeader("Content-length", mybody.length);
http.setRequestHeader("Connection", "close");   
http.send(mybody);

I sent xml data to my server and get return response successfully in Safari browser but i can't do it in iTunes LP environment. So what is the problems?