I had a similar problem and struggling, googling for 1 day. But it was a simple mistake that instead of:
{http://ws.somecompany.com/services}ValidateUser
It should be
{http://ws.somecompany.com/services/}ValidateUser
Der XML-Schema-Designer (XSD-Designer) ist ein grafisches Tool, mit dem Sie ein Schemaset auf unterschiedlichen Abstraktionsebenen visualisieren können. Der XSD-Designer besteht aus den folgenden Hauptkomponenten:
a web services client library. It includes a WSDL Parser,a XSD Schema Parser and Validator and XML Parser and serializer and an API and command line tool for dynamic WSDL inspection and invocation.
XRay is a free XML editing enviroment. Now in its second major release, XRay provides support for XML Schema (XSD) and an integrated online XML tutorial system.
G. Bex, F. Neven, and J. Van den Bussche. WebDB '04: Proceedings of the 7th International Workshop on the Web and Databases, page 79--84. New York, NY, USA, ACM Press, (2004)