Possible to use a e-scooter brake as a Gas lever?

Hello, 

I have started to upgrade my e-scooter with an Vesc. 

The problem is that I broke the gas/Speed thumb chuck and I now want to use the break- Thumb chuck. I installed an Servo tester to convert the hall signal. Now in the Vesc tool the settings are wrong, because if I lift the thumb chuck the red bar is getting in the wrong direction, and the motor speed decreases.

Is there an way to invert the signal or chance the settings?

Best Regards, 

Max Pfannkuch