[Serusers] Cisco 79xx authentication (off-topic to some extent)

Apologies for the extent to which this is off-topic. I've seen related mails in the serusers archive, and expect that this community can at worst tell me where better to post. I have a Cisco 7960 on my desk, and can't manage to make it authenticate to either the iptel.org SIP server or to an Asterisk system where I'm also made welcome. I'm not seeing problems with X-Lite. Between Google, serusers archives, and the Cisco docs, I can't see what it is that I need to do. I don't yet have my own SIP server running, so I'm not in a position to make server-side experiments. Any help will be greatly appreciated. Thanks in advance. Best regards, Niall O'Reilly PGP key ID: AE995ED9 (see www.pgp.net) Fingerprint: 23DC C6DE 8874 2432 2BE0 3905 7987 E48D AE99 5ED9