I'm trying to add a custom error handler that should fire every time there is an application error

namespace LogService

{ public class ErrorHandling : ApplicationEventHandler {

    protected override void ApplicationStarted(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
    {

        umbracoApplication.Error += new EventHandler(umbracoApplication_Error);

    }

    void umbracoApplication_Error(object sender, EventArgs e)
    {

        Exception ex = HttpContext.Current.Server.GetLastError().GetBaseException();
        EmailProvider.SendErrorEmail(ex);
        HttpContext.Current.Response.Redirect("~/");
    }
}

}

The event is binded (the code is executed on start) but the event doesn't fire...

Umbraco version 6.1.6

PS: I' don't want to change global.asax inherit class if possible (this meant to be part of a pluggable package)

Thank you