I've found a solution for a server with ZCS , but remember this is GLOBAL SETTINGS so ALL ACCOUNT and EVERY DOMAIN will do this operation:
we work as zimbra user
What is this command for:
zimbra:~$ zmprov mcf zimbraSpamHeader "" zimbraSpamHeaderValue ""
This command modify general working settings and set Zimbra Header/Value to null, so when spamassassin with procmail try to intercept messages based on this header they skip the tagged message and it is delivered to inbox instead of junk.
If you log into webmail client you can still see your messages tagged as [***SPAM***] (remember that this tag must be manually entered into Admin GUI ->Global Settings -> AS/AV -> Antispam Control -> Subject prefix) and you could move them manually to junk pressing Junk button or filter anyway you like.
The most important thing is that POP3 users now can see incoming spam messages and filter them locally by subject filtering!
How to revert:
Warning: zmcontrol stop && zmcontrol start is required to enable modify.
zimbra:~$ zmprov mcf zimbraSpamHeader "X-Spam-Flag" zimbraSpamHeaderValue "YES"
Hope this could help someone like me who needs this operation to be solved as soos as possible
PS: You can verify your global spam settings with
clear && zmprov gacf|grep -i spam