Define all Xdomain callbacks

On IE9 XDomain request may abort.
Don't ask me why, but the solution is to define all callbacks. @see http://social.msdn.microsoft.com/Forums/ie/en-US/30ef3add-767c-4436-b8a9-f1ca19b4812e/ie9-rtm-xdomainrequest-issued-requests-may-abort-if-all-event-handlers-not-specified