I don't actually know what's going wrong with your code, but you might consider creating your own implementation of ListModel, which is pretty easy and straightforward if you extend AbstractListModel. Then, keep a reference to the list model in your surrounding code, and you can do the updates easily.
Hope that helps, Guido
I’ve looked at a lot of different solutions, and in my humble opinion Aspose is the way to go. Here’s the link: http://aspose.com