how to use webrequest with redirect page

Hi everyone,
I am a beginner in using webrequest. I am trying to access paypal by using Httpwebrequest/Httpwebresponse. I have posted my login&password, but got stuck with redirect page that asks me to re-enter Username and password again. Please see my code below.
Any experts please advise,
Uri uri = new Uri("https://www.paypal.com/cgi-bin/webscr?cmd=_login-submit");         data = "login_email=xxx@hotmail.com&login_password=xxx";         byte[] buffer = Encoding.UTF8 ...