A simple proxy hack to facilitate routing traffic from an app via a proxy. Build BasicProxy as a standalone DLL, and then add the we.config stuff to your app's web.config.

BasicProxy.cs

using System;
using System.Net;
using System.Windows.Forms;

namespace BasicProxy
{
    public class MyProxy : IWebProxy
    {
        private readonly string _proxyUri = GetAppSetting("ProxyUri", string.Empty);
        private readonly string _proxyUsername = GetAppSetting("ProxyUsername", "user");
        private readonly string _proxyPassword = GetAppSetting("ProxyPassword", "password");
        private readonly string _proxyDomain = GetAppSetting("ProxyDomain", string.Empty);

        public ICredentials Credentials
        {
            get
            {
                if (string.IsNullOrEmpty(_proxyDomain))
                {
                    return new NetworkCredential(_proxyUsername, _proxyPassword);
                }
                return new NetworkCredential(_proxyUsername, _proxyPassword, _proxyDomain);
            }

            set { }
        }

        public Uri GetProxy(Uri destination)
        {
            return new Uri(_proxyUri);
        }

        public bool IsBypassed(Uri host)
        {
            return false;
        }

        public static string GetAppSetting(string key, string defaultValue = "")
        {
            var asr = new System.Configuration.AppSettingsReader();
            string result;
            try
            {
                result = asr.GetValue(key, typeof(string)).ToString();
            }
            catch (Exception)
            {
                result = defaultValue;
            }
            return result;
        }
    }
}

web.config

  <appSettings>
    <add key="ProxyUri" value="proxyUri" />
    <add key="ProxyUsername" value="proxyUsername" />
    <add key="ProxyPassword" value="proxyPassword" />
    <add key="ProxyDomain" value="" /> <!-- ignored if empty string -->
  </appSettings>

  <system.net>
    <defaultProxy enabled="true" useDefaultCredentials="false">
      <module type = "BasicProxy.MyProxy, BasicProxy" />
    </defaultProxy>
  </system.net>