Clients using the .net sdk 2.0 work for Services using doc-literal-wrapped services generated by jbossws 1.0.x on jboss 4.0.5 for me so far. I did not try the .net 3.0 sdk so far.
Your could try to switch to doc-literal (if you are not already using this style) or using the .net 2.0 sdk (Is it possible to use them in parallel?)
Not sure if this would fix your problem, but could you move up to jbossws 1.2? I have a 1.2 web service working correctly with a .Net 3.0 C# client, using both doc and rpc style.
I tried jbossws 1.2 installed on top of jboss 4.0.5 without success : I get the same error.
I will try C# now to see if it works better with jbossws
I didn't try the doc-literal yet, I will do it also.
Finally I tried wstools with style=document
Visual Basic cannot get along with this.
It seems that MS SOAP Toolkit is using rpc style, and that the high level API uses a namespace in the parameter definition, which is incompatible with jbossws. However, since this toolkit is superseded by .Net there is no way
The conclusion is : one must use the call Serializer.SoapAttribute("xmlns", "", "", "") and the low level API to get it work.
With C#, on the contrary, everything goes fine, and a webservice call is two lines of code.
Haven't tried your specific example, but have had no problems calling webservices from Excel. Here be the link I used to get things going.
Maybe there will be some clues in the MS generated code.