NTLM authentication with WebServiceClient

We have a stand-alone SOAP server that we're trying to make use of from CloverETL's WebServiceClient (CloverETL Designer 3.4.1.010P).

Our SOAP server is responding to the initial request with a "401 Unauthorized" message, with "WWW-Authenticate: Negotiate" header.

401 Unauthorized
Server: POE::Component::Server::SOAP/1.14
WWW-Authenticate: Negotiate

FORBIDDEN

The following appears in the Console on the CloverETL side:

WARN  [Axis2 Task] - Unable to respond to any of these challenges: {negotiate=Negotiate}

, and from there the call fails with an "Unauthorized" exception:

org.jetel.exception.JetelRuntimeException: Component [WebServiceClient:WEB_SERVICE_CLIENT] finished with status ERROR.
	at org.jetel.graph.Node.createNodeException(Node.java:535)
	at org.jetel.graph.Node.run(Node.java:514)
	at java.lang.Thread.run(Thread.java:722)
Caused by: com.opensys.cloveretl.component.ws.exception.SendingMessageException: org.apache.axis2.AxisFault: Transport error: 401 Error: (Unauthorized)
	at com.opensys.cloveretl.component.ws.proxy.a.b(Unknown Source)
	at com.opensys.cloveretl.component.ws.proxy.a.a(Unknown Source)
	at com.opensys.cloveretl.component.WebServiceClient.a(Unknown Source)
	at com.opensys.cloveretl.component.WebServiceClient.execute(Unknown Source)
	at org.jetel.graph.Node.run(Node.java:485)
	... 1 more
Caused by: org.apache.axis2.AxisFault: Transport error: 401 Error: (Unauthorized)
	at org.apache.axis2.transport.http.HTTPSender.handleResponse(HTTPSender.java:313)
	at org.apache.axis2.transport.http.HTTPSender.sendViaPost(HTTPSender.java:200)
	at org.apache.axis2.transport.http.HTTPSender.send(HTTPSender.java:76)
	at org.apache.axis2.transport.http.CommonsHTTPTransportSender.writeMessageWithCommons(CommonsHTTPTransportSender.java:400)
	at org.apache.axis2.transport.http.CommonsHTTPTransportSender.invoke(CommonsHTTPTransportSender.java:225)
	at org.apache.axis2.engine.AxisEngine.send(AxisEngine.java:438)
	at org.apache.axis2.description.OutInAxisOperationClient.send(OutInAxisOperation.java:402)
	at org.apache.axis2.description.OutInAxisOperationClient$NonBlockingInvocationWorker.run(OutInAxisOperation.java:442)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
	... 1 more

I have this working with Basic authentication, but am attempting to get pass-through Windows Authentication to work.

I have set Username, Password, and Auth Domain in the WebServiceClient properties. Is there a trick to this?