Disable user password change form

Hi,

We have a domain, which is using external LDAP authentication. Users should change their passwords in different way, so I want to disable password change option from Carbonio -> I set the COS advanced value "Prevent user from changing password". But in the web UI I can still see option Auth and it opens a form where user can change the password. Of course when user try to change the password UI says "something went wrong" because of the COS option. This causes unnecessary contacts from users to the support. How I can hide the whole Auth part from the settings or just disable the form with message which says that the password change is not possible from webmail.

Thanks!