Ollie,

   You will want to use the SoapHttpClientProtocol class.  It will allow
you to make late-bound calls to SOAP services.  As a matter of fact, when
you create proxies in VS.NET, the classes derive from this, and all method
calls actually package up calls to the Invoke method on the same class.

   Hope this helps.

Ollie,
Been down that road :( Unfortunately, there's not many googlets out there
with help on this and related topics. Here is some (modified) code I wrote to
do this. I also included a few other useful lines which set credentials,
timeouts, and connection limits. I hope it helps.

John

public ServiceInit()
{

    MyService WebService = new MyService();

    RegistryKey hklm = Registry.LocalMachine;
    RegistryKey hkNterWeb = hklm.OpenSubKey(@"SOFTWARE\MyApp\WebService");
    RegistryKey hkConfiguration = hkNterWeb.OpenSubKey(@"Configuration");

    WebService.Url = (String) hkConfiguration.GetValue("WebServiceURL");
    ServiceTimeout = int.Parse((String)
hkConfiguration.GetValue("WebServiceTimeout"));
    ServiceConnections = int.Parse((String)
hkConfiguration.GetValue("WebServiceConnections"));
    hklm.Close();

    WebService.Credentials = System.Net.CredentialCache.DefaultCredentials;
    WebService.Timeout = ServiceTimeout;

    HttpWebResponse res = null;
    HttpWebRequest req = (HttpWebRequest)WebRequest.Create (WebService.Url);
    res = (HttpWebResponse)req.GetResponse ();
    ServicePoint currentServicePoint = req.ServicePoint;
    currentServicePoint.MaxIdleTime = ServiceTimeout;
    currentServicePoint.ConnectionLimit = ServiceConnections;

}