Bindings for speaker device type

Hi there - I posted this question on the git repository but not sure where it’s best addressed. I’m currently writing a plug-in for av devices and I’m hoping to code them in such a way that I can implement them in home kit via home kit buddy as ‘speaker’ device types. At this stage they are indigo relay devices with onOffstate = bool, mute=bool and volume = int. they do show up as speakers in the elgato eve app, but just show up as unsupported devices with no control in the home app. Is there any way for me to specify them so they work in the native home app? I’m just looking for a simple on off toggle at this stage - I know I could just add them as switches, but I’m trying to develop them as neatly as possible. Any advice welcome!