There is a back door. That's the good news.
The bad news is that you have to call Nortel Tech support, who will send you an affidavit, that must be signed by some "high up," then faxed back to Nortel. Nortel will give you a one-shot password into an FTP server(maybe WEB by now) to get the password killer, which will only work on one box (based on information you supplied in the affidavit).
And if you're not a current contract customer, this might cost you a few bucks.
Maybe the procedure has changed, but this is the way it used to be.
Good Luck,
Scott