how to create button in internet explorer?

Question

I am developing a simple c++ program inside Microsoft Visual Studio. This program will later be convert to DLL, in order to register it to Internet Explorer.

Inside my program, I would like to do like this:

 if flag=1,
   toolbar_button = green;
 else
   toolbar button = red;

I want to create a simple button on the Internet Explorer, and the button can reflects the color that I pass from my c++ program.

How can I achieve this?

Update: So far, I follow this manual http://msdn.microsoft.com/en-us/library/aa753588%28VS.85%29.aspx#details_script . I do it inside my Windows XP and IE8. It still does not work. No button appear on the IE toolbar.