CRM for Phone app - how to disable field according to Security role

Hello,

We are on CRM 2015 update 1 online and are using the new CRM for Phone app.

On our appointment form, we disable/enable some fields according to the security role of the user by using Javascript getUserRoles and UserHasRole. This works fine in the browser, but does not seem to work in the Phone app.

How can we do the same in the Phone app?