How to use the ExtendedWebBrowser

Question

Hi all!
I'm a c# beginner and, yes, i'm new in this forum too.
I'm writing a c# program where i need to open more tabs in a webbrowser object.
I've look a while in the web and I found this article:
http://blogs.artinsoft.net/mrojas/archive/2008/09/18/newwindow2-events-in-the-c-webbrowsercontrol.aspx
I wrote that code in the ExtendedWebBrowser class.
Now I'm writing the code to setup handlers for NewWindow2 and point ppDisp. (See the code).
My question is: Where can i find the ExternalWebBrowser object in the design mode? Because i don't find it in the toolbox and i've got this error when i try to debug:

 private void Form1_Load(object sender, EventArgs e)
        {
            InitializeBrowserEvents(webBrv);
        }

Argument 1: cannot convert from 'System.Windows.Forms.WebBrowser' to 'ExtendedWebBrowser'    because webBrs is a WebBrowser object.

At last, How can I unregistered the event when i close a tab?

Thank you for support.