IIS 7.0 install two SSL certificates with two different host headers

You can't assign different SSL certificates to sites that are only differentiated by host headers. You would need to have the sites on separate IP addresses.

Another option is to setup a wildcard SSL certificate (which you could then apply to all sites hosted under *.example.org on the server.) There is a catch though - you still can't apply the certificate through the GUI. Instead you need to use a command line to apply the certificate.

http://www.sslshopper.com/article-ssl-host-headers-in-iis-7.html http://blogs.iis.net/thomad/archive/2008/01/25/ssl-certificates-on-sites-with-host-headers.aspx