Hello there. I have never gone from Mahara into Moodle so I don't know the system but when you say you see them in the Moodle list but not for becoming admin - are you saying that they appear in the general users list ie Settings>Users>Accounts>Browse list of users - but NOT in the Settings>Users>Permissions>Site administrators?
That would make sense … that one sees only local accounts in Moodle … because other mnetted accounts are 'fetched' from the mnetted servers other wise.
However, one does see 'mnet' users when Assigning System roles in the 2. Roles are restricted to Manager or Course Creator.
Now comes the 'fun' … I'll use myself as an example:
I've 6 other servers mneted to a Moodle 2 instance. In the other servers I used the same name, login name, and EMail address as the account in the Moodle 2 (different password, however). Thus, when I pull up a list of 'potential users' and do a search for login name, I see all those accounts, but there is no designation in the potential users list that shows which mnet server.
In your case, where is there is only Mahara and your Moodle, that might not present a problem.
But, have seen many times that admin users should create some true student accounts and login as those users to see exactly how things work/don't work.
Actually, if one thinks about it, probably a good idea (for security purposes) that there is restriction such as this. Yes, it does make it more inconvenient for the Admin user. But, it also helps prevent someone else from acquiring the 'keys to the city' so to speak … crack one account and cracker has access to many/all.
Did read an interesting article about a high profile persons experience with such an event. This person had various accounts … twitter, Facebook, etc, etc. 'tied together' and with rather trivial methods a hacker was able to acquire access to one account, thus leading to acquisition of and control of other accounts until, eventually, nearly all were 'taken over'. Basically, e-identity was compromised.
Search Google for 'identity theft stories' if one desires an education.
my 2 cents ... 'spirit of sharing', Ken