KC868-Hx Alexa change luminosity

[elconfa]

Hello, I bought the component to connect Alexa to my Home Domotic. Does it is possible to change the luminosity of the light? In Sinric or Alexa application I can change the luminosity, but from Alexa serial interface I read only RELAY-SET-255,2,1 (for ON) or RELAY-SET-255,2,0 (for OFF).
The KC868-Hx Alexa Voice Module does not change the "value", for example from 255 to 125 for 50% of luminosity. 
How it is possible to send the "value" to the serial port?

Thanks in advance

Massimo