Catch HTTP code 401 and prevent standard login dialog

Question

Hello,
in my FLEX application I load some data from a Java servlet. I use URLRequest and URLLoader to load the data. The servlet requires basic authentication. I use a custom login dialog to get the users credentials. Everything works fine except when the user provides wrong credentials. Then the servlet returns HTTP code 401 and FLEX automatically shows a standard login dialog. I'd like to show a custom dialog instead. However I have not found a way to catch the 401 code and prevent the standard dialog from showing. Is there a solution for this?
My code:
var encoder: Base64Encoder = new Base64Encoder();
encoder.encode(context.userId + ":" + context.password);
var credHeader: URLRequestHeader = new URLRequestHeader(
     "Authorization", "Basic " + encoder.toString());
var loader: URLLoader = new URLLoader();
var request: URLRequest = new URLRequest("http://.../userinfo");
request.method = URLRequestMethod.GET;
request.requestHeaders.push(credHeader);
loader.load(request);
Thanks,
Florian

Answer 1

Sure,
this is my custom login dialog:
and this is the default login dialog:
The application runs on Adobe AIR version 2.6.