The plug is on the top of the backing plate, as opposed to most others that have it on the bottom of the plate. But what I've used to get mine adjusted is the parking brake. "Supposedly" just backing up should cause the self-adjusters to kick in, but it doesn't seem to work that way on mine. I back into parking spots and my garage all the time, but at 15K, an adjustment was definitely evident (more weight transfer forward when coming to a stop).
I find a reasonably empty parking lot, then get moving a few mph, and SLOWLY apply the parking brake. Did this a few times and braking was much better. Note that you should apply the parking brake slowly as, on mine anyway, it was very touchy between slowing it down and locking up the rear wheels. Amazing how loud and attention-getting a set of locked up rear wheels in a parking garage is ....
I'm not sure if just cycling the parking brake while stopped would have the same effect, or if motion is required. I might try cycling it next time.