One piece pin, press fit in insulator. You have to carefully press it down, in a controlled fashion. Do you have an arbor press, hydraulic press... drill press, vise, welders vise grips... see where I'm going? "Controlled fashion" is the key phrase. ;-)
If the answer is no to all of the above... you might be able to "tap" it down with a support (3/8" drive socket) and a drift. Careful... easy does it, etc, etc, etc. Worst case scenario... you go to far, then the other way, then back, then again... until the pin gets (increasingly) loose in the insulator.
