There should be no reason why the installed Spamassassin in RHEL should be used rather than the one in Zimbra, the Zimbra SA is called as a perl module and has nothing to do with the RHEL SA (I have SA installed on my system and it's not causing problems).. You should, of course, make sure that the installed SA is disabled from starting, as it's normally run as a daemon.
There should also be no problem running sa-update to update the rules in Zimbra, I used to use rules-du-jour without problems. You should use sa-update and point it to the correct Zimbra directories that contain your rules and use the 'channels' to update them. Details on running sa-update and the channels are on these pages:
SareChannels - Spamassassin Wiki http://daryl.dostech.ca/sa-update/sa...date-howto.txt OpenProtect's SpamAssassin sa-update channel SpamAssassin at Arda.Homeunix.Net
That should point you in the right direction.
