Is it possible to get kopete to delete(?) it's knowledge of a servers (self signed) certificate?

Things worked perfectly until the self signed certificate of the xmpp server expired. When a new cert was generated, kopete cannot connect anymore. I get a "malformed packet" error. kopete works fine to other servers. Using the same user/pass on a similar kde/kopete system that never connected the server with the new cert works.

Is there a way to have kopete "start over" for this one server?

Thanks