Session events not fire in IIS 7.5 and Windows server 2008 R2

Hi all,

I have developed MVC4 application in VS Express 2012 for Web. In my website, I have a site statistics which is calculated by using Session_Start and Session_End events. In dev environment (IIS Express) these events fire when having new user accessing but in production server (IIS 7.5, Windows Server 2008 R2) nothing is happened.

Here are my Session events in Global.asax.cs

protected void Session_Start(object sender, EventArgs e)
        {
            Session.Timeout = 20;
            Application.Lock();
            Application["OnlineUsers"] = (int)Application["OnlineUsers"] + 1;
            Application.UnLock();

            // Update counter to DB here...           
        }

        protected void Session_End(object sender, EventArgs e)
        {
            Application.Lock();
            Application["OnlineUsers"] = (int)Application["OnlineUsers"] - 1;
            Application.UnLock();

            // Update counter to DB here...
        }

Some parameters in Web.config which I have tried to config but these events not fire :(

<system.web><compilation targetFramework="4.0" debug="true" /><authentication mode="Forms"><forms loginUrl="~/Account/Login" cookieless="UseCookies" domain="" timeout="20" protection="All" requireSSL="false" /></authentication><pages enableSessionState="true"><namespaces><add namespace="System.Web.Helpers" /><add namespace="System.Web.Mvc" /><add namespace="System.Web.Mvc.Ajax" /><add namespace="System.Web.Mvc.Html" /><add namespace="System.Web.Optimization" /><add namespace="System.Web.Routing" /><add namespace="System.Web.WebPages" /><add namespace="MVCVideo" /></namespaces></pages><sessionState mode="InProc" timeout="20" /></system.web>

Now I don't know how to fix this in production server. Could anyone help me, please?

Thanks and best regards,

Android Lee