Additional permissions

[airiarte]

Hi and thanks for the great work. I have an application that asks for email and public_profile permissions on login and it works perfect. Later on, I want to ask for public_actions if the user wants to publish something and I don´t know how to do it. Would you please lead me to how I can achieve this?. If I ask for email, public_profile, and publish_actions during the initial login then two screens are shown for requesting read permissions first and then write permissions which discourage users to login.
Thank yoy very much.
Ariel