Reply to traktor 2.5 mapping

Hey guys. i have a kontrol x1 trying to mapp a few things in traktor 2.5 in nhl mode, so 2 questions.

1.i cant mapp a toggle button like fx 1 on, to a knob, it says unapropriate control. Any way around this, or am i missing something ? So i wanna mapp it to a knob not a button.

2.lets say i have a knob mapped to the first knob on my fx unit. now i want to mapp it so, that when i turn the knob all to the right on my midi controller, that it only goes to half of the maximum value, so the center in traktor.

any help apreciated