Disabling softkeys on polycom SIP 320s

I’ve been trying to disable the ignore and reject buttons on my Polycom phones as well as set a max and min volume and can’t find where. I’ve been looking in the sip.cfg and phone.cfg but can’t seem to find the proper values to control these things. Polycom’s documentation doesn’t explain how to do these things and I’ve looked at a lot of google results to no avail. Has anyone successfully done this?