setting session variables

I have a form with a formview and using the insertitem template.  After a user clicks the insert button I redirect to a menu page using this code:
 Protected Sub FormView1_ItemInserted(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.FormViewInsertedEventArgs) Handles FormView1.ItemInserted
        Response.Redirect("menu.aspx", True)
    End Sub
 Before it goes to the menu, I want to set a session variable equal to what a user entered into a text box.  I tried doing this
 
Session("tmpItem") = Request("myitemTextBox")
I put this before the response.redirect but this did not work.  Where do I need to put this?

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