Add Web Reference failure in BizTalk 2006 projects

I ran into the following nuisance after building a new VPC with .NET beta 2, WinFx (Sept CTP), the WinFx VS.NET extensions, and BTS 2006. With this configuration, Add Web Reference in BizTalk projects stopped working. I would get an unhelpful error message saying something like "Failed to add Web reference". It would work in other project types, but not BizTalk projects. Then I remember reading Mike Taulty's post about what happens to Add Web Reference when you install the WinFX VS.NET extensions. The install adds a <soapExtensionImporterType> to devenv.exe.config so wsdl.exe and Add Web Reference will generate WCF proxies. Once I commented out the WCF <soapExtensionImporterType>, Add Web Reference began working again in my BizTalk projects.