Presenting Sonoff SWV water valve to HomeKit

I’ve been using a Sonoff SWV water valve for a while and want it be recognised as a water valve / irrigation accessory via HomeKit bridge.

It currently presents as a switch, which is fine and works in Apple Home, but I’m not able to set a running time in the same way I can with my Eve water valves. The result is that I end up turning it on and forgetting to turn it of…

Where do I start with configuring the switch as a valve and passing that property to Apple Home through HomeKit bridge?