MelCloud Water Heater power button

Hello all, we have a Mitsubishi Ecodan water heater.
We added Melcloud support, and we can see it from the Melcloud app and website.
In HA most of the functions are present, but not the general On/Off toggle, even if in the documentation it says that a “Power” parameter is present for the water_heater entity.

Here the documentation paragraph:

In the top left corner, the On/Off toggle for the Ecodan:

Any suggestion on how to access that button? Thank you very much!