Thank you very much for the answer and sorry to bother again!
Can you be a little more specific?
I know I have to edit the 50-user file but what should I put there?
Where is the global settings? How can I disable spam/virus/dkim inside the global settings?
How, inside the $policy_bank{'MYUSERS'} I can enable spam/virus/dkim?
I'm posting my 50-user file
Thank you very much for taking the time to answer my questions!