如何以编程方式为IIS7创建子域？

I'm writing a SaaS app in C#/ASP.NET, hosted with IIS7. I want to create a personalized subdomain for every customer that signs up, i.e. fred.mydomain.com, bob.mydomain.com, each of which will point to the same app, just with a different skin per customer. I'm writing a SaaS app in C#/ASP.NET, hosted wi