How do I display menus in the menu bar from my app?

How do I display menus in the menu bar from my app?
I want to activate the main menu bar menu and possibly a sub menu when a user presses some button in my app. I know this can be done because I've seen it in applications which exercise other applications (MACRO APPS). I was able to do this by posting WM_SYSCHAR messages and then pumping throught them, but this flashed the menu too fast. I need the user to see the menus open one at a time. I would be very greatful if someone knows how this is done.
You can e-mail me at [email protected]
Thanks in advance.