I had made a post last week about the problems that quite a few of us were facing with Mango. Finally, after a lot of discussion on the gnome-i18n Mailing list, the missing bits of information came forth from Olav.
To summarize it:
For any language, not listed in the New Account Request interface on Mango, please send a mail to accounts at gnome dot org with the specifics of the case. A language can be missing from the Mango interface in any of the following cases:
The current documentation does not mention these cases and their solutions. I would not mind lending a hand in here, if the suggested editing requires for volunteers. (Its a wiki but given the special nature of information, its best to wait for an approval.)
However there is a small catch in all of this. The accounts at gnome dot org, queue handling also sees period of inactivity. Hence, perhaps that bit might need a little attention.