Sort_warning notification

I would like to call procedure(which is empty for test) when sort warning is happened. I have enabled service broker, created a queue to receive messages, created a service on the queue that references the event notifications contract, and finally created an event notification. But when sort warning happens(I can see it in profiler), there is no message in queue and SP is not invoked. Have I missed something?

br, Simon

CREATE QUEUE dbo.SortWarningsQueue
WITH STATUS=ON,	
ACTIVATION 
			(
				PROCEDURE_NAME = dbo.process_sort_warning_event,
				MAX_QUEUE_READERS = 5,
				EXECUTE AS OWNER
			);

CREATE SERVICE SortWarningsService
ON QUEUE dbo.SortWarningsQueue
(
    [http://schemas.microsoft.com/SQL/Notifications/PostEventNotification]
);
GO

--Create the database event notification
CREATE EVENT NOTIFICATION NotifySort_Warnings
ON SERVER
FOR SORT_WARNINGS
TO SERVICE 'SortWarningsService','current database';
GO