Moodle networking (MNet)

Hi all,
I'm planning to use Moodle Network for an organization having 15 Moodle sites.

We plan to configure this 15 sites in a master-slave model, with one site working as a "portal" (the "master"), where everyone logs in.
The other sites, where courses actually are, will work as "slave".
Nobody is supposed to log in directly in "slaves" sites.
Also we plan to manage users and enrollment from the master site.

I've a couple of questions:

I'm missing something or I'm only able to enrol students, and not teachers, to courses on remote sites? (I'm using Site Administration -> Networking -> Enrolments)


I've seen that users are created and updated on the remote site when the user actually "move" to the remote site or when the user is enrolled to a course (as a studend, as of above) using Networking Enrolments.
Is there any way to "push" users to a remote site, either for creation and update?
I mean a way for an administrator to force the immediate creation of a user on the remote site and a (cronned?) task that sync changed user data to remote site.

Lorenzo