I recommend to find a factory bracket for the front tow hook if you can, and use it. You can buy them second hand or at a junkyard sometimes for cheap. They are designed to distribute a load on the front of the ZJ, But in a bind you can attach one right to the uni-body. I have used this technique on one of our ZJ's in the past. It was strong and we didn't have any issues pulling on it. But I do not recommend it as a permanent solution.
Here is a write up:
http://www.eriejeeppeople.com/…id=13709&st=0&#entry13709