protecting “on code” and “off code” from beeing changed by a user?

[mszag]

hello everybody,

i am looking for a way to protect specific settings, within the "CallFeatures"-menu.
Especially the "on code" and "off code" settings for call forwarding from beeing changed by a user.

I have set up following settings:

forward.always.on_code = *011
forward.always.off_code = *010
forward.busy.on_code = *021
forward.busy.off_code = *020
forward.always.on_code = *011
forward.always.off_code = *010
forward.no_answer.on_code = *031
forward.no_answer.off_code = *030

The user is able to change the values for these code, because it is editable from the phone menu itself.

Can i make these fields "protected" in some way or just "hide" it from the user, so that they are not able to changes its values?

Thanks for any advices!