EvoHome integration issue

About 8 months ago I’ve integrated Honeywell’s EvoHome using a custom device handler found on this site (worldhouse47531 : Evohome Heating Zone R3.4 ).

It works fine. However, I’ve added a new room with new radiator control in my EvoHome, and I don’t know how to add this in my SmartThings device. Does anyone know how to do this?

Regards, Hans