failure.as

var a:XML = <request command="run-command" />;
var r:URLRequest = new URLRequest("http://localhost/service.php");

r.data = a;
r.method = URLRequestMethod.POST;
r.contentType = "text/xml";

var l:URLLoader = new URLLoader();
l.addEventListener(Event.COMPLETE, function(e:Event) {
    trace("success", l.data);
});
l.addEventListener(IOErrorEvent.IO_ERROR, function(e:Event) {
    trace("failed", e);
});
l.load(r);

success.as

var a:XML = <request command="run-command" />;
var r:URLRequest = new URLRequest("http://localhost/service.php");

r.data = a.toXMLString();
r.method = URLRequestMethod.POST;
r.contentType = "text/xml";

var l:URLLoader = new URLLoader();
l.addEventListener(Event.COMPLETE, function(e:Event) {
    trace("success", l.data);
});
l.addEventListener(IOErrorEvent.IO_ERROR, function(e:Event) {
    trace("failed", e);
});
l.load(r);