Controlling a High Torque BLDC with analog signal

Hi everyone!

I am new in this world as you will be able to see when you read my question… So i am trying to control a BLDC motor on my ground vehicle (a prototype for a maintenance vehicle) which has its own controller.

Then i am using a CUAV v5+ as autopilot with Qgroundcontrol, where i am changing parameters to obtain on the AUX outputs differents PWM signals according to the movement of left joystick from a ChinoWing T30S ground station which i convert from PWM to analog signal with a converter, which send that final analog signal to the motor controller.

I got some problems, i need a 0-5V range to control the velocity on my motor controller, but i need too a reverse mode too, so i need a double range of 0-5V from the center of the joystick to upside and downside.

The reverse mode or direction change can be done on the motor controller sending a GND signal, so the principal questions are:

¿Can i implement this control in a better way?(Using other hardware/software configuration)
¿Any help to configure that double range on qgroundcontrol to obtain that voltage values?

Thanks in advance,