form authentication slidingExpiration not sliding

[Ben S]

framework 1.1

in our webapp, we are using forms authentication.

=================
Auth Section from web.config
=================

<authentication mode="Forms">
<forms name="loginauth" path="/" loginUrl="loginauth.aspx"
protection="All" timeout="5" slidingExpiration="true">
</forms>
</authentication>

After sign in, I use the following code to get the expiration date/time from
the current authentication cookie, but the expiration time does not change as
I refresh the page, or ruturn after visiting other pages on the site. The
current time does change with each hit of the debug page. This is causing an
issue because our user is getting timed out.

==================
output from debug page
==================

Current Time: 10/11/2004 11:53:31 AM
Auth Cookie Expires: 10/11/2004 12:52:27 PM
Auth User Data:

==================
Source that generate the output
==================
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
Dim ctx As HttpContext = HttpContext.Current

If ctx.Request.IsAuthenticated Then
Dim id As FormsIdentity = CType(ctx.User.Identity, FormsIdentity)
authCookie = id.Ticket
End If

Response.Write("<br><br>Current Time: " & Now().ToString)
Response.Write("<br>Auth Cookie Expires: " &
authCookie.Expiration.ToString)
Response.Write("<br>Auth User Data: " & authCookie.UserData)
End Sub