VKB BtnTester see more than 32 buttons (I test there now), so something are wrong in your setup, revise connections.
I don't know if Falcon BMS support recognize more than 32 buttons (this is limited by Windows DImput), but since this game engine are old, is not improbable. DCS World for example see up to 128.
If is the case, using SVMapper, you can use buttons above 32, sending keypress.
