I haven't updated my profile yet (my bad), but this is on CentOS 5, actually.
I did make the change in amavisd.conf.in and still no-go on the dspam. I'm not sure what the deal is. I still haven't determined the cause of the issue or a solution.. getting more spam than normal though
/opt/zimbra/dspam/var/dspam/system.log hasn't been updated, and in the message headers there is no dspam information.