This sort of problem posted again and again in this newsgroup simply
because some of us thinks that Web Services is just a method with
WebMethod attribute, rather that a set of messages in a document based
mesaging platform. even a simple web method like this can cause
interoperablity problem

[WebMethod]
public Employee[] GetEmployee()
{
    Employee[] emps = new Employee[10];
    return emps;
}

I think Microsoft is part to blame for making developers thinking that's
how to write web services. everytime you create a new asmx in VS.Net in
give the HelloWord

// WEB SERVICE EXAMPLE
// The HelloWorld() example service returns the string Hello World
// To build, uncomment the following lines then save and build the project
// To test this web service, press F5

//    [WebMethod]
//    public string HelloWorld()
//    {
//        return "Hello World";
//    }

Using tools like XmlSpy (my favorite) or CapeClear WSDL editor certainly
helps to make a better interoperable web services.  Christian Weyer's
contract-first tool for web services is a great tool to achieve this as
well, thou' i have it installed never really touch it. One of this
should be the first tool every web service developer should have in
their toolbox after the HelloWorld introduction

regards
erymuzuan