Set your trap on top of the ground. paper clip a piece of shingle not much bigger than the pan to the pan. On one side of the trap jaw, let's say the dog side put the scat on the other thee sides, just missing the jaw or hinge points put guide sticks. The ones at the hinges should be no smaller than 1" and 2" in dia. are just fine. The free jaw side can be blocked such that no approach is possible. On the side with the scat you should have your backing beyond the scat. Make the overall set appear to be a trail...a "walk Through" toilet set. If you have some Bob cat gland lure you can add a bit at the base of the free jaw blocking. It sounds like you have sac oil...so you could use this in place of the gland lure. One last thing, on that shingle sprinkle some dirt...just enough to make the shingle disappear.
