HttpHandlers / Modules :: Sending Second HttpWebRequest In Sync With First Request

Using a Windows application I am sending a web request to a web page and getting the response back using the following code

HttpWebRequest oRequest1 = (HttpWebRequest)WebRequest.Create(url);
oRequest1.ContentType = "text/xml";
using (Stream stream = oRequest1.GetRequestStream())
{
stream.Write(fileBytes1, 0, fileBytes2.Length); //fileBytes1 - contains the data of first request
}
HttpWebResponse Response1 = (HttpWebResponse)oRequest1.GetResponse();
->The above code works fine
But I need to enhance the code to accomodate following additional scenario
->Send another request to the same web app and
->get the response back

The first request sent contains the credentials to access the web application the second request sent doesn't have credentials, it must use the credentials of first request. I am using the same (following) code for the second request too. I get an error saying that it's looking for credentials

HttpWebRequest oRequest2 = (HttpWebRequest)WebRequest.Create(url);
oRequest2.ContentType = "text/xml";
using (Stream stream = oRequest2.GetRequestStream())
{
stream.Write(fileBytes2, 0, fileBytes2.Length);
}
HttpWebResponse Response2 = (HttpWebResponse)oRequest2.GetResponse();

So how do I accomplish this? Should I be sending the second request using same session or same connection?