FOUND 1) Hold the Alt key down and press the corresponding access key to open the desired menu. 2) Keep the Alt key pressed! 3) Move the menu selection (using the arrow keys on the keyboard) to the desired menu item. 4) Press the Print Screen key.
I highly recommend Snagit for taking screen captures for documentation. It has a timer option to give you time to open menus and popups. Great markup features along with organizing images.