Totally not in the IIS configuration, not even mentioned there, had to search the net for about two hours, here is the secret magic to have this working when all the sites are under https:
http://www.sslshopper.com/article-how-to-configure-ssl-host-headers-in-iis-6.htmlIf you look down below, you will find a binding command. For as long as this is not executed, no reference to the secure port can be achieved when multiple sub domains are sharing the same certificate.
