I'm only familiar with the autoplane feature of FL2.
What I would do is survey the area of the pad. When done, Hit auto plane. It will calculate the best possible slope. Disregard the result and manually adjust the slope and direction how you want it. Pretty straight forward. Then ( because you don't want to cut anything ) go to the highest spot of the pad and offset the blade higher so that it just skims the  ground in that spot. Then get at it.