Mindmapping tool

This is a small experiment I’m doing to create a mind mapping tool.
Simple functions like lineTo are used to create cool applications like this.

My only concern here is that if I’m creating this as a standalone desktop application, how do I save the map. I’m going to create an entire xml file of the visual map and then save it.
I think 3rd party tool needed to be used.

Is there any other option?

Note: The attached file is Flash 8 version