Here's a look the the door popper system I have rigged up. You can't really tell, but their is a cable that hooks up to the locking mechanism where the outside door handles use to be. Next, I ran that cable down to the bottom of the door jamb where it hit s pulley. From their it changes directions and runs along the bottom of the door jamb to the solenoid.
( you can barley make out the pulley in right hole in one of the photos attached)
Door popper worked great the hole where the rubber door stop use to be.