Interactive Gantt chart & save functionality

I've been trying to develop an interactive Gantt chart within Web Dynpro ABAP. Things have been going fine and altough there doesn't seem to be much documentation available, I've managed to get a simple Gantt chart WD application up and running.

The following is said in the documentation:

"It is possible to store changes made within the displayed Gantt chart as data structures again in the back end."

I understand this that if I do changes to the Gantt chart, I should be able to "track" these changes in my code (and for example save the changes to database or whatever). Anyhow, I am not able to get this done. I've put break points to the event handler methods, and read the XML from the context node, but the XML has not changed.

I also enabled the SAVE functionality for the Gantt (in the XML), which made the Save-button visible. If I click the save-button, I would assume that at this point the XML is updated with the refreshed chart data. Anyhow, this does not seem to happen. The XML seem to have lost the relevant part of it (=basically everything under the <graph> tag, which would include the changes (this same problems was addressed also before: )).

Any hints are welcome. I guess that this should not be impossible. I assume that for example in cProjects (which uses Gantt chart a lot) is using this functionality - unfortunately I don't have an access to a cProjects system.

Kind regards,

Karri