Are you using 1.9 or 2.0? I don't have a Moodle networked 2.0 to test it out but it works with 1.9 -but they do have to have logged into the other Moodle first. Have the users you want to make site admins actually gone into the other Moodle via Mnet yet?
We are running multiple 2.0 instances and we cannot add MNet users as Site Admins either. Even once they have logged in to their native instance and used MNet to come across to another instance, their name does not show up in the list of possible users to promote as Admins. This is kind of a pain for us, but we manage. Any tips would be welcomed.
In Moodle 2 you need to goto the admin panel and in Plugins goto enrolment method and enable Mnet enrolment method. It should then appear in the admin network section of the drop down.
To use Mnet enrol you have to enable it at course level using the enrolment link.
Admin is as fare as I can see the only one who can enrol by the Mnet method.
Hope that helps
That sounds like a case of "The system can't trust the Admin." I would argue that there are far more dangerous settings an Admin can change than allowing an MNet user to be an Admin.
We required this feature, so our only recourse was to expand the LDAP context to allow the user to natively log in to the various Moodle instances. This causes all sorts of duplicate user issues where we get username1(native user), username2(Mnet user), etc. where the users are actually the same.
If, for example, you use a central Mahara instance, those various users are treated as separate despite being one and the same.
