You would need to work with various API's in order to add the website to IIS and to which ever DNS server that you use.
I not worked with IIS to do this, but have worked with SimpleDNS's API for their DNS server to read, create, and delete DNS records, and it took several weeks of coding and testing to get the system correct.
If you do use SimpleDNS for your DNS servers then their API is fairly simple to work with and they also provide a component for Classic ASP that you can use to talk to the primary DNS server.