>>Superb! Thanks once again Viv. What is interesting is that all the email is now being sent, but the code never hits the SendCompletedCallback.
>>
>>Oh, it also does not seem to be running asynchronously as I don't get control back in the UI for quite a while.
>>
>>One of these days I'll understand C# :(
>
>Viv,
>
>I commented out the wiatHandle.WaitOne(); and then my code stopped hanging. Do I need that line of code in there? Is it just in the wrong place?

I think you need it - otherwise the whole PostAWBS method will exit before the async calls are complete. Are you sure all the emails were sent when it was removed ?

P.S Ignore the update to my last post. As you found the SendCompletedCallback will fire whether it is static or not.