Can a BackgroundWorker call RunWorkerCompleted events from an ASP.NET Web application?

Hello,

My RunWorkerCompleted event handler is not called for a BackgroundWorker in an ASP.NET Web application.

The BackgroundWorker is created during an asynchronous postback of a button.

I also continue to call the postback event recursively in order to maintain a reverse ajax session.

Here is my code:  (Although this is a dll, I tried the same code in the web page.  With the same result.)

{
    public class Wait
    {
        public int NumberOfSeconds { get; private set; }

        public Wait()
        {
            NumberOfSeconds = DEFAULT_NUMBER_OF_SECONDS;
        }

        public Wait(int iNumberOfSeconds)
        {
            NumberOfSeconds = iNumberOfSeconds;
        }

        public void StartWait()
        {
            backgroundWorker1 = new BackgroundWorker();
            backgroundWorker1.WorkerSupportsCancellation = true;
            backgroundWorker1.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
            backgroundWorker1.RunWorkerCompleted += new RunWorkerCompletedEventHandler(backgroundWorker1_RunWorkerCompleted);
            backgroundWorker1.RunWorkerAsync();
        }

        public void StopWait()
        {
            if (backgroundWorker1.WorkerSupportsCancellation == true)
            {
                // Cancel the asynchronous operation.
                backgroundWorker1.CancelAsync();
            }
        }

        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            Thread.Sleep(NumberOfSeconds * 1000); //in milliseconds
            throw new Exception("DialogWait: timer has elapsed."); //this causes program termination from an uncaught exception
        }
//this method is never called
        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (e.Cancelled == false)
            {
                throw new Exception("DialogWait: timer has elapsed.");
            }
        }

        /// <summary>
        /// background worker
        /// </summary>
        private BackgroundWorker backgroundWorker1 = new BackgroundWorker();

        /// <summary>
        /// default timeout (in seconds)
        /// </summary>
        private const int DEFAULT_NUMBER_OF_SECONDS = 30; 
    }
}

The exception in the DoWork method terminates the program due to an uncaught exception.  The RunWorkCompleted event handler is never called.  (Even without the exception thrown.)

Any suggestions?