KeyDown and volume button

Xojo has added KeyDown and KeyUp events to a mobileScreen, however they aren’t trapping the volume buttons.
I’m using these in AndroidStudio and hoped to use it in Xojo too.
What I’m trying to do is trap the button press of a “selfie trigger”.

Does anyone know how to get those values to show up in the MobileScreen?
I’m wondering if there is some other setting I need to configure.