First, flatten your pole with an axe where you are going to set the trap. Then use 3 roofing nails, 2 on one side and 1 on the other side in the center. The space between the two nails on one side and the one on the other side should be just over an inch apart. Now set the trap so one jaw is on the outside of the 2 nails and the other jaw is on the outside of the 1 nail. Squeeze the jaws into the nails as you set it. Your trap will stay there in place.
Now lift the two springs up above the top jaws at an angle and you can put a bough through both rings forming an arc above the trap.
This is a great way to set any size conibear on a pole set. Sometimes I even set on a pole for a diving set using 3 nails. The following pictures can be enlarged by clicking on them.
Here's a three nail set I use for otter and beaver on a diving pole