Yeah, I belive just adding the menu option to the main menu should do it.
Open up the script cc_terminal and copy the code from there, except the csc_proceed() line, and then just paste it into a new script "mev_pause_boxes", then go to obj_player's Step event to find the code where the pause menu is created when you press the pause button - add a new line here that adds that new mev_pause_boxes option.