MQTT Switch setup in button card

Hi All,

My setup:

  1. B&R PLC publishing and subscribing from mosquitto broker.
  2. VM running HAS
  3. Using MQTT explorer to verify communication to the broker.

Create a switch on my bash where I can switch a light on and off.

What I did in HAS:
Installed MQTT
Added the switch to my config file:

    - unique_id: living_beam1_switch
      name: "Living beam1"
      state_topic: "homeassistant/living/beam1/switch"
      command_topic: "homeassistant/living/beam1/switch/set"
      availability_topic: "homeassistant/living/beam1/switch/available"
      payload_on: "ON"
      payload_off: "OFF"
      state_on: "ON"
      state_off: "OFF"
      optimistic: false
      qos: 0
      retain: true

The topics are visible in MQTT explorer. I also can publish to them through settings-> devices&services → Mosquitto broker.

So all fine until this point.

Now I want to add a button card. In the button card I can find my entity switch.living_beam1.
Now I start to struggle. What do I need to add in action and hold action?

When I take toggle, nothing happens
I can only get it partly working when I use the “Call service” - MQTT-publish and “hardcode” the topic and payload.
Issue is that I can not toggle the light in this case.

I hope somebody could guide me in the correct direction.
Thanks in advance.