Torqueedo & Herelink, Motor won't reverse

Hello,

I am working on a USV powered by a torqueedo motor that I am struggling to set up. The torqueedo travel motor is connected to a Cube orange using the Japan Drones RS485-to-Serial converter board. The USV will be controlled via Herelink.

My problem is that I am not able to make the motor go in reverse. With a neutral throttle stick, the motor runs at 50%, and it stops with the stick fully in reverse. I suppose that this could be fixed by enabling allow negative thrust in the joystick menu in qgroundcontrol, but this menu is no longer available in qgroundcontrol on herelink. Is there any workaround, or would I simply have to downgrade the herelink?