Regarding Session_End and Application_End methods in asp.net

I'm trying to implement a class (lets call it CustomerConnection class) which implements System.Web.HttpApplication interface. I tried to implement two events session_end and application_end events in this class in this way:

public class CustomerConnection: System.Web.HttpApplication
{


    protected void Session_End(object sender, EventArgs e)
    {
        HttpApplication application = (HttpApplication)sender;
        HttpContext context = application.Context;
        SqlConnection connection = context.Items[Database_Con] as SqlConnection;
        connection.close();

    }

    protected void Application_End(object sender, EventArgs e)
    {
        HttpApplication application = (HttpApplication)sender;
        HttpContext context = application.Context;
        //someotherEvent
    }

But it seems these events are not getting executed neither for the application end or session log out.

How should i make these events get´executed ? Is it like i have to notify to certain other event?

I'm just creating a new object of customer class. is it enough to get these events executed or my approach is fundamentally wrong?

Please help me out

Thanks in anticipation

You need this in global.asax:

<%@ Application Language="C#" Inherits="CustomerConnection"%>

Caveat, I've never tried this, I found it here: http://www.codedigest.com/Articles/ASPNET/34_Adding_CodeBehind_for_Gloabalasaz_x_file_in_aspnet_20.aspx