Yamaha Musiccast Binding: playerControls channel

I am trying to link a pico (Lutron) audio controller keypad to control Yamaha musiccast streamers. So far, I have managed to turn each musiccast device on/off (power), and can select streaming service as input (e.g., input=tidal).

However, there are some channels that are either not implemented in the binding, OR possibly are implemented by I cannot see the channel.

Is there some way for me to “extend” the binding to implement the functions I want? Or, if someone is aware of how to access these channels from the Musiccast binding, please educate me!

Note that it does appear from the Musiccast binding wiki page that playerControls channels should be available for playerControls play and pause, but I cannot find them in the binding (at least not from the PaperUI) - in fact I don’t see any zone or playercontrols channels at all.

Assuming I need to implement these as extensions to the musiccast binding, please guide me - I am very new to OH so lay it out like I am an idiot please.

Here is the API (from Yamaha) code that would need to be implemented:
http://{host}/YamahaExtendedControl/v1/netusb/setPlayback?playback={command}

Where {command} is chosen from “play” / “stop” / “pause” / “play_pause” / “previous” / “next” /
“fast_reverse_start” / “fast_reverse_end” / “fast_forward_start” /
“fast_forward_end”

The above function is from the Network/USB APIs (section 7 of the Yamaha musiccast basic API). But the channel values in the Musiccast binding are not defined as far as I can see. I have been trying unsuccessfully to send the command via the NetRadioUSB_Player channel, but nothing I have entered in the command string works. I have tried “play”, “pause”, playback=“next”, “next” and several other variations to try to send these commands, but nothing is working.

Since I know how to send the command via http, I would imagine I should be able to extend the model to add this channel manually and be able to send these commands via my extension, but I don’t know how to extend the model to add a channel like that.

Here is rule for one of my attempts trying to use the existing channel interface unsuccessfully (keep mind I have tried many variations per above)…

configuration: {}
triggers:
  - id: "1"
    configuration:
      itemName: Coach_Road_Final_Master_Bath_Bath_Wall_Bathroom_Audio_Button_3
    type: core.ItemStateChangeTrigger
conditions: []
actions:
  - inputs: {}
    id: "2"
    configuration:
      itemName: Yamaha_MusicCast_MasterBathroom_NetRadioUSB_Player
      command: playback="next"
    type: core.ItemCommandAction