No, he doesn't have the buttons, that's the DZ-1002. Besides the push buttons the 1002 also provides circuitry to keep the leds on between switch throws. Other wise they just wink at you when you fire the switch.
Follow the wiring from the switch. The power wire is at the switch, the green and yellow are opposite paths to ground. So ground is going down to the 1002 and the buttons determine the path to the ground wire. So the ASC needs to replace the functionality of the 1002 with a relay.
For non-derailing, you are just providing another path to ground by grounding the green or yellow. This isolated rail switch is wired in parallel with the ASC so that either one can trigger the switch.
