Dimmer not manage White Level

Hello, i have a shelly rgbw2 managed with HA, but it seems to be impossible to manage the white level brightness with HomeHabit.
The only option i have is to switch on/off and to manage main brightness value, but it seems not possible to manage the white level brightness.
This is a big problem because in my specific case i am maniging with the rgbw2 a single white led strip, and the only way i have to set the brightness is using the white level bar. On HA and Alexa there is the possibility to manage the white level wth a specific bar, on HH is not possible.
Can you explain how can i manage this?
Thank u