"keyboard-driven" Drop-down menu


I want to implement a drop-down menu into a project of mine.
I have found few tutorials on how to do this, however I need one that functions with the keyboard, not the mouse. I am using "SlasherXGames" method
He provides the completed original project file (http://tinyurl.com/hc4g8oq)

Here is what I have so far (https://www.dropbox.com/s/2p0kyo4atti7dhh/Dropdown Component2.gmx.zip?dl=0)
I want to use the left/right direction keys to scroll between the menus, use the enter key to select, and then the up and down keys to select a choice from that menu.
I have moving between the menu's down, I can select them too, but I cant scroll through and make a selection.

is there a way I can successfully implement the "scroll through" function of the main menus into the menu selections as well? I have creation code on the menu objects in the room to make it work, but I don't know how to add CC to the list of menu items.
in obj_menuItem -> create-> I have

menu_functions2 = "first";
self.name = "button1";
self.b_up = "button1";
self.b_down = "button2";
so that I may highlight the first menu list option.

I feel like I may be one or two lines of code away from making this function work.
I hope I've provided enough explanation.
Any and all help is appreciated.