Remap Bluetooth headset buttons on Android

I have my Bluetooth headset and it has 3 buttons: - BACK/Volume- - NEXT/Volume+ - PLAY/STOP I need to map one button (any of these) to take action after pressing (e.g. turn on the flashlight, or directly make a call to a specific person). I found https://android.stackexchange.com/questions/218857/remap-bluetooth-headsets-media-key-android-9 , so I installed AutoVoice and Tasker, but I am not able to call action after the button on the headset is pressed (of course, I am pretty newbie with AutoVoice and Tasker, so maybe my fault). Could you please help me?