WCF in IIS7 via WAS: is HTTP required?

God, could I use more acronyms in the subject?

So, this isn't a WCF question as much as an IIS7 one, but figured the WAS
team would probably be more active here. I am hosting a WCF service in IIS7
on Vista RTM over net.tcp which is working fine. The problem comes when i
try to remove the http binding in IIS (either via the command line or admin
console). I get an "invalid HRESULT" error. Is this known behaviour, or a
bug?

Thanks!

John St. Clair