Hi,
I’m looking at the error message you pasted in your original post, and these two lines caught my eye:
The type must derive from System.Web.Services.Protocols.SoapHttpClientProtocol.
The type must have the attribute System.Web.Services.WebServiceBindingAttribute.
I wonder if you tried adding the Microsoft assembly System.Web.Services to your References folder in the project where you are adding the web reference and see if that resolves the web service invocation warning issue.
Cheers,
Daniel.