I'm looking at getting an SSL certificate and I think the SAN type is what I need. However, Can I easily add further domain names to be covered by the certficate in the future. E.g. I have www.example.com on my server. In 6 months time I decide to build and host a new site on the same server and give it the URL www.example2.com. Would I then be able to add the new domain to the existing certificate?