I wound up getting it on one of the contracts. The target was above me but not close to the climbable wall so I shot an arrow at the ledge and got him when he came to investigate. Thanks for the replies though.
(Props to dsluckay for the sig/avy) (Trophy bar by:Thunder)
I had the same issue and was ready to throw in the towel and start over, but i found one contract that was made for it. I cant remember where it was, but it's preety close to where you get that contract! and it's a small cabin with 7 guys or so And the target is on top of it. Now it's only the co op mission left wich is actually pretty fun. Great game