ASP.Net FormAuthentication response.redirect to IIS Virtual Directory - redirect

Question

Have a LoginForm and default asp.net with to buttons on default asp.net. My Target is to after sucssefully Login redirect to default.aspx and by button click connect to IIS Virtual directory.
Login is working fine but the Problem is that i get after button click LoginForm again to authenticate.What should i do to be able to be redirected to virtual directory without authenticate again.
MY LoginForm CodeBehind
protected void Login1_Authenticate(object sender, AuthenticateEventArgs e)
{
string UserName = Login1.UserName;
string Password = Login1.Password;
bool RememberMe = Login1.RememberMeSet;
string adPath = ConfigurationManager.ConnectionStrings["AD"].ConnectionString;
string DomainFQDN = ConfigurationManager.AppSettings["DomainFQDN"];
string PermitedLoginGroup = ConfigurationManager.AppSettings["PermitiedLoginGroup"];
string DomainNetBiosName = ConfigurationManager.AppSettings["DomainNetBiosName"];
try
{
LdapAuthentication adAuth = new LdapAuthentication(adPath);
if (true == adAuth.Authenticate(UserName, Password, DomainNetBiosName))
{
Session["UserName"] = UserName;
FormsAuthenticationTicket tkt;
string cookiestr;
HttpCookie ck;
tkt = new FormsAuthenticationTicket(1, UserName, DateTime.Now,
DateTime.Now.AddMinutes(30), Login1.RememberMeSet, "your custom data");
cookiestr = FormsAuthentication.Encrypt(tkt);
ck = new HttpCookie(FormsAuthentication.FormsCookieName, cookiestr);
string ckName = ck.Name;
if (Login1.RememberMeSet)
ck.Expires = tkt.Expiration;
ck.Path = FormsAuthentication.FormsCookiePath;
Response.Cookies.Add(ck);
string strRedirect;
strRedirect = Request["ReturnUrl"];
if (strRedirect == null)
strRedirect = "Default2.aspx";
FormsAuthentication.RedirectFromLoginPage(UserName, RememberMe);
Response.Redirect(strRedirect, true);
}
}
catch (Exception ex)
{
}
}
Default2.aspx
<%# Page Title="" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="Default2.aspx.cs" Inherits="LoginForm.Default2" %>
<asp:Content ID="Content1" ContentPlaceHolderID="MainContent" runat="server">
<asp:Button ID="ButtonProd" runat="server" OnClick="ButtonProd_Click" Text="Prod" />
<asp:Button ID="ButtonTest" runat="server" OnClick="ButtonTest_Click" Text="Test" />
</asp:Content>
I am trying to do somthing like this in button click method but i am redirecting again to LoginForm and if i give my credentials again i am able to access Virtual Directory on IIS
protected void ButtonTest_Click(object sender, EventArgs e)
{
HttpCookie ck = (Request.Cookies[".ASPXAUTH"]);
Response.Cookies.Add(ck);
Response.Redirect("Response.Redirect("http://webserver.ad.com/VirtualDirectory",false);
}
Could someone give me some tips...Thanks in advance....