Thanks.
I am aware of the limitations of IIS7.5, but one IP-one domain is exactly what I am trying to do. That should be no problem. Multiple domains on one IP is a no-no, I know.
I turns out that the real culprit is GoDaddy, who didn’t update my ip settings, so both domains were targeting the same ip address. Took me a while to figure that one out. I didn’t update this post because I wanted to check if the setup would work with the proper ip settings.
So I changed them two days ago, and now the domain doesn’t resolve any more.
Le Sigh, I’ll get there in the end!