Setpoint sending numeric value to mySensors Node


I’m trying to make a thermostat that will actually be able to work by itself (in case openhab crash) as well as to be controlled by openhab using MQTT and MySensors. I actually have a node setted up to send the temperature to openhab and it works great, but now I would like to create a Setpoint item that would send that value to the same node.
How should I set the item in openhab and how do I make the node listen to that message?

I found out about using something like V_Status or so in the node receive function, but I don’t understand how it works actually and can’t seem to find the right ressource for this…