I understand your frustation. Keypads are supported by the Community, there is no official Smarthings support for a keypad.
Use the DTH at miriad/Centralite-Keypad/master, or you may get it at this link: https://raw.githubusercontent.com/miriad/Centralite-Keypad/master/devicetypes/mitchpond/centralite-keypad.src/centralite-keypad.groovy
Along with these two SmartApps
- Lock Manager (includes keypad support)
- Smarthome Exit and Entry Delay
Hopefully should get you up and running. I’m using this exact setup with an Xfinity/Centralite Keypad.