ZHA Zigbee Volume Knob from GUI Slider?

Configuration
1

I have this code in my config that makes a small slider to control the volume of one of my amp outputs (didn’t post the other 5) but it is not enough to integrate with a Zigbee button. Everything works except the volume for the amp.

input_number:
  av_vol1:
    name: Living
    initial: 14
    min: 1
    max: 38
    step: 1
  av_vol2:
    name: Dining
    initial: 14
    min: 1
    max: 38
    step: 1

shell_command:
  set_vol_to_slider1: >-
    bash -c 'echo -ne "<11VO{{'%02d'% states('input_number.av_vol1')|int }}\r\n" | nc 192.168.2.156 8080'
  set_vol_to_slider2: >-
    bash -c 'echo -ne "<12VO{{'%02d'% states('input_number.av_vol2')|int }}\r\n" | nc 192.168.2.156 8080'

Is there something I can add to the config to make the entities I need? I’ve made switches for the speakers to turn them off and on, which work with the remote.

Thank you