[Axis2] Server did not recognize the value of HTTP Header SOAPAction

[Fan, Jan-fon]

Hi,
I am trying to use Axis2C client API from Linux to consume a web
services that is created by Microsoft .NET in Windows.
But the return of axis2_svc_client_send_receive function indicates:
   
<soap:Fault xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/
<http://schemas.xmlsoap.org/soap/envelope/> ">
<faultcode>soap:Client</faultcode>
<faultstring>System.Web.Services.Protocols.SoapException:
Server did not recognize the value of HTTP Header SOAPAction: .
     at
 System.Web.Services.Protocols.Soap11ServerProtocolHelper.RouteRequest()
     at System.Web.Services.Protocols.SoapServerProtocol.Initialize()
     at System.Web.Services.Protocols.ServerProtocolFactory.Create(Type
 type, HttpContext context, HttpRequest request, HttpResponse response,
 Boolean&amp; abortProcessing)</faultstring>
<detail/>
</soap:Fault>
   
   
It seems to me that there is something wrong in the SOAPAction, what
might be the reason causing this problem.
   
Thanks,
Jan-fon