Hola Roberto,
No se como querras hacerlo, pero a mi esto me funciona perfecto:
Codigo .aspx
Código PHP:
<%@ Page Language="VB" AutoEventWireup="false" CodeFile="Default.aspx.vb" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Button ID="Button2" runat="server" Text="Button" />
</div>
</form>
</body>
</html>
Codigo .aspx.vb
Código PHP:
Partial Class _Default
Inherits System.Web.UI.Page
Protected Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button2.Click
Response.Redirect("~/login.aspx")
End Sub
End Class