Ajax data filter on json which is really xml
===

I'm doing a GET with ajax using dataType jsonp to bring in a small xml file from a server on another domain which I don't own and can't change.   Any dataType other than jsonp fails with a "Origin localhost is not allowed by Access-Control-Allow-Origin.  Fine.  

The problem is that the server returns the same xml response when I say it's jsonp and jQuery doesn't seem to like this.   dataFilter doesn't seem to help as the instant I refer to the returned data I get an "Uncaught SyntaxError: Unexpected token <" error.   Maybe there's some other way to use the dataFilter setting?

My code is reproduced below: 

        $(document).ready(function(){  
	  $.ajax({  
	    type: "GET",  
	    url: "https://b2b.firstenergycorp.com/invoke/ ... very long url... ",  
          dataType: "jsonp",
          dataFilter: function(data, type){
             if(type == "xml") alert("returned xml!");
             var newdata = data.replace(/</g, '{');   // Firebug complains about this
             newdata = newdata.replace(/>/g, '}');
             return newdata;
           },
        jsonp : "callback",
        jsonpCallback: "jsonpcallback"
       });  
       function jsonpcallback(returndata) {
          alert( "data returned: " + returndata );
       };
    });      

![Chrome complains about xml format][1]


  [1]: http://i.stack.imgur.com/e8hHf.png