The HAL setup would depend on how the system is configured to detect the selected gear.
For your setup I think that you would need some HAL logic to convert the 3 inputs into a gear number. Or you could modify the component to suit your system.
As it stands the component expects either an integer number for the selected gear, or a single input bit to be set for each gear. Your system has 8 inputs but they are used in combinations. You could potentially wire pairs of switches to each lever to give binary patterns to be sent to a weighted-sum component, but I think that modifying the component above to have three sets of input bits would be better.
It might actually be easier to use the VFD speed and measured spindle speed to auto-detect the selected gear. (Better still would be to use a speed sensor or encoder on the motor). This is what I do with my milling machine which has 8 gears.