Making Axis work with HTTP/Basic authentication and a VB.Net client

[Kevin O'Rourke]

I'm trying to do authentication for my Axis web service using HTTP/Basic
over SSL, as this seemed to be the easiest option.  The client is
written in Visual Basic .Net 2005.

I've added the HTTPAuthHandler to my WSDD file:
...
 <service name="NtiAuth" provider="java:RPC">
  <requestFlow>
    <handler type="java:org.apache.axis.handlers.http.HTTPAuthHandler"/>
    <handler type="soapmonitor"/>
  </requestFlow>
  <responseFlow>
    <handler type="java:org.apache.axis.handlers.http.HTTPAuthHandler"/>
    <handler type="soapmonitor"/>
  </responseFlow>
...

However no authentication is happening.  The VB.Net client seems to be
waiting for a "401 WWW-Authenticate Basic" error from the server, to
indicate that the server wants authentication.  Axis isn't sending a 401
but is instead just happily giving me a null username and password.

Does anyone know how I can persuade Axis to send back a 401 error?

Kevin