Issue above was related to the fact that the proxy class on the C# side was not generated properly .. Should be derived from : Microsoft.Web.Services3.WebServicesClientProtocol Unfortunatly the there is still an issue related to the content type of the respons sent from the server. With the request the content type is Content-Type: multipart/related; type="application/xop+xml" But on the repons of this request the content type is set to : Content-Type: text/xml;charset=UTF-8 WSE cannot support this feature ! http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=1099016&SiteID=1 View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4109865#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...