Also, local (keypad HIM) control can be masked out, so you might need to change one or more of the mask parameters to allow the HIM to control the drive.
I would recommend saving all the parameters in the HIM before you change anything. Then change the control source, reference source, and masks as necessary to perform your tests. Once you're done and you want to change the programming back to normal, you can simply load the saved settings from the HIM to the drive and be done.