RoboDK setup analogout for robot extruder

Has anyone successfully configured the analog output in RoboDK to adjust the motor speed on a robotic extruder? The robot in question is a KUKA, and RoboDK is the Professional version. I managed to control the analog input directly through the SRC code, but in RoboDK, I was only able to set the analog output to either 0V or 10V, corresponding to the minimum and maximum speeds, respectively. I can't make RoboDK have fine control of the extruder, that is, the extruder doesn't have a constant speed, but rather reduces the extruder speed based on the robot's movement.