Up to now, our web services don't allow to edit a "Moodle object" (course, user, activity ...), except rename a category and rename a course.
Our WS are designed to be used by GenDep (or another deployement application) to deploy a learning arrangement, not to adapt an existing one. This may evolve in the future.
Currently, these WS are also designed to contextualize the learning arrangement, by using moodle objects that already exist on the server, without modifying it. Exemple given, when the learning arrangement model includes users, you can import existing users from the moodle server when you deploy the model.