Since the .fla file currently works by reading in a .txt file. You would have to update it to accept more than one xml file at a time as well. That might be the difficult part.
Our contribution was creating the wizard that creates the xml file, and the parsing php that takes the xml file and writes the .txt file that the open flash charts actually parses. And then creating an xml editor to allow you to view and update the xml by hand when necessary.
The xml editor is easy to use, but it is very basic and was not the primary focus of our development. Other than giving you the structure at a glance and and easy way to select the xml in the code, you are still basically editing the xml by hand. However it will give code hints for available properties in the xml and the like.
