Background threading with InfoPath

[Rob]

I have a background task (using C#) that is started in the _Startup function
that is defined by InfoPath. This task needs to update the XDocument with
values it computes. I understand that one cannot directly modify the
"thisXDocument" object from the worker thread because it's part of the UI
thread. I have defined an event and delegate that is called when the
background thread needs to update the XDocument. Normally, I would have this
callback use the Invoke pattern to update the XDocument so that there is no
threading sync issues. Unfortunately, that method is not available as part of
the InfoPath object model.

Bottom line: How can I safely update the XDocument from a background
thread???

Thanks...