<defaultProxy enabled="true" useDefaultCredentials="true">

undefinedproxy bypassonlocal="True" proxyaddress="address

It works fine with MS ISA and for one our client who use SQUID,but it doesn't work on another site with SQUID proxy server- still returns
HTTP status 407: Proxy Authentication Required 

I am able to set proxy details for individual web services proxy with the code like the following

        IWebProxy proxyObject = new WebProxy(txtProxy.Text, true);

//special case for Basic authentication (from http://www.xmlwebservices.cc/index_FAQ.htm )

        proxyObject.Credentials = new System.Net.NetworkCredential(sUser, sPassword);

        ws.Proxy = proxyObject;

        ws.PreAuthenticate = true;//from http://www.awprofessional.com/articles/article.asp?p=27574&seqNum=3

        ws.AllowAutoRedirect = true;
and it works, but I prefer to have one centralized solution, that useDefaultCredentials expected to provide.

Microsoft acknowledged that useDefaultCredentials doesn't work for SQUID proxy server , but they fixed it in Visual Studio SP1, not in .Net Framework(actually I haven't try to use .Net framework 3.0 - may be there is a fix for this?).

At the moment I am planning to add SetProxy functionality for each Web Services call,HttpWebRequest call and replace  dataset.ReadXml(url)  with HttpWebRequest.GetRequesst - boring work.

Can anyone suggest better solution?