If you got here from search engine you already know that WSE is integrated into Visual Studio 2005, but not 2008. You also know that if add reference to the web service that implements WSE you would get proper class in Visual Studio 2005 but not in 2008. The common advise is use VS 2005 to do the import, or use svcutil.exe.
The easiest solution though is just to open Reference.cs file and replace System.Web.Services.Protocols.SoapHttpClientProtocol with Microsoft.Web.Services3.WebServicesClientProtocol manually.
Also, here you can find how to make plug-in available in VS 2008 UI.
