How to bind the ip address while sending soap request?

Question

I need to bind a specific ip address while sending soap request in c#.net web application. How should i do this.

private static HttpWebRequest CreateWebRequest(string url)
{
     HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(url);
     webRequest.ContentType = "text/xml;charset=\"utf-8\"";
     webRequest.Accept = "text/xml";
     webRequest.Method = "POST";
     return webRequest;
}