Sony Bravia TV and Amazon echo dot

Hello my friend
I have sony bravia tv and Amazon echo dot and I like my echo dot control my tv.

On HA I add the braviatv platform allows you to control a Sony Bravia TV.
And my hassio control the tv, on an off source and volume up an down.

I add the Alexa cloud and discover all my device on Alexa app.
Also my tv .

But when I give commend to set volume up or down see can do that.
If I give commend to turn on or off it do that.

How can I control the volume by Alexa dot ?

Someone know?