Well, if you have the siren, it can be of help to just add it to Homey, just select any device from the Ring Security app. The device will be added as a Generic Z-Wave device and will do nothing, but in the devices advanced settings some useful information will be shown such as the Device ID, ProductID and Product Type ID. Please make a screenshot of that information and publish it here. (no promises though!)
The reason for adding the V2 keypad (and also V1) is basically the whole reason I wrote this app, to be able to use a real Alarm Keypad with Heimdall. Have a look at it and play around so you’re all set when your new Homey Pro arrives!