Custom device: thermostatic valve

[heinh]

I use eQ3 max thermostatic valve and the domoticz plugin is working fine , this plugin create 4 device type per valve:
A switch selector with the different modes, a thermostat setpoint, a temperature and “valve”Type general in % that show the actual opening.

I would like to have the view of the 3 last parameters on the same widget and be able to have a graph of the log combining the 3.
My first idea was to create a virtual sensor with the 3 values (similar to Temp_baro) and a script that copies value from the real.
To create such custom device type, tried to add a file in the domoticz/dzVents/runtime/device-adapters folder and refer it in the adapter.lua file but this doesn’t appear as a device type. I suspect that I do not looking ion the correct folder

Is there a method to create such custom device?

Regards,
Henri