I'm running ISA 2004 Enterprise Edition, 2 servers belonging to one array.
As part of some OWA publishing rules we have a local certificate generated by a stand alone CA which also runs on the first ISA 2004 server.
This certificate belongs to a web listener for one of the rules (local host to Exchange). The certificate is a one year issue, has expired and I cannot see a way to renew it.
Note: the commercial external based certificate, webmail.companyname.co.uk is fine and doesn't expire for another year.