What zwave frequency is your hub and what is the siren? Seems like this is a region frequency issue.
Based on those videos, the hub hasn’t been put into into z-wave inclusion mode and a z-wave device can’t be added if the hub isn’t looking for it…
The V3 hub doesn’t go into z-wave inclusion mode when you use that scan for devices option which is why the steps I mentioned above are necessary for z-wave devices that don’t support S2 security.
I have tried multiple times to set this as a dimmer and I never see the option without changing the handler to not the one you made. Could you walk me through a step by step of getting this to show as a dimmer?
Are you changing it to a copy of my handler that you renamed or to some other handler?
Did you have the latest version of my handler installed before joining the device?