MIDI mapping shift key and Numark Party mix

I have a Numark party mix dj controller and I am trying to map all of the functions. First off I was wondering how to map my function key. There are four buttons on each deck and a fifth button that changes the functions of the buttons, between cue, loop, sample, and effect. I have looked through the posts and no one has been able to map this change function button successfully. My idea is that there is a shift key that you can map. I was going to deal with only two of these functions by mapping the shift key to my function changer. I would only be able to use two of the functions, which I can deal with but the issue is that once the shift key is clicked I cannot toggle it off. Under the advanced options I cannot make this button a toggle or anything accept a default button. How can I turn the shift key off, and did anyone find out how to make the function key on the Numark Party Mix work?