[Serusers] blocking CID continuing using radius authentication

I would like to use the ATAs features to block the CID for anonymous calls.

At the same time I wouldn't like to break my accounting done by Radius Authentication.

This is the ser.cfg about radius auth for international calls:

if (!radius_is_user_in("From","int")) { sl_send_reply("403","Internazionali non abilitate"); break;

I use to authenticate the "From" field so if I disable the CID on the ata I will receive an anonymous from field. What do I have to authenticate to mantain a working accounting? Do I have to authenticate against "Credentials"? What is the difference between Credentials and from headers?

Regards

Rosario