If I understand it right, you just want to know, how to wire a rotaryswitch to fsBus to detect the rotating-direction, right?
för this, you can use rotaries witch any number of contacts per rotation which can be divided with 4 (sorry for my bad english)
you just wire pin 1,5,9 etc to key1, pin 2,6,10...to key2, 3,7,11... to key3 and pin 4,8,12...to key4 on the FSKey card.
then you have to select the four key as a rotary and give it the function you want to have on this.
that´s all folks
greez phil