Our scenario

We have been running with SBS 2003 for several years and our
Certificate is pop3.olddomainname.co.uk (where our old domain name is
now changing)
For one reason or another, we've never got it qualified to DNS,, and
with only 2 of us accessing OWA, we just use https://<external_IP>/exchange
and our PDA's could get email OK on the move.

Now, we have built a linux box to run the support part of our website,
we have a new external domain, so we got support.newdomainname.co.uk
added to DNS
We need the PDA/iPhone to use SSL so that they and OWA use the 443
port so that the linux box is free to use port 80 for http

I went to the CEICW and went through the steps,
Do not change connection type
Allow access to following....
Selected 'Create a new web server certificate' and put in
support.newdomainname.co.uk
followed through to the finish.

However, if I go to Control Panel> Admin Tools>Certification
Authority, it still shows pop3.olddomainname.co.uk

I had exported the 'new' certificate and loaded it to the PDA, which
works with SSL but says the certificate is invalid each time it
'pushes'

I'd like some advice as to what's wrong here please.
Many thanks