IMO that would be a misunderstanding of what you have read or
a poorly written document as Web Services and making the transition
to a Service Oriented Architecture is supposed to be what the .NET
Framework initiative is all about.

I think therefore it is correct to say that the difference is which other
tools and applications are included and not which functionality or
technologies are supported.

I do not know of that limitation. EA adds on a bunch of tools, like Visio,
to make your job easier. One of the nicest is Application Center Test. Now,
there may be some additional tools for web services in EA, but you can build
a service in any version, except perhaps the Visual Language Standard
editions.

I happened to find this MSDN article [1] that describes what
applications and tools come with different editions of Visual Studio.NET