Yep... I've been running ASSP for longer than i have been using Cpanel... WHen I moved over to my new server back in February, I was able to move my ASSP install over and tweak a few configs and it was up and working.
The main thing is inserting assp into the mailstream...
Code:
local_interfaces = 127.0.0.1.125
Put at the top of your exim.conf to make exim listen on localhost on port 125 (and not listen on your public ips or on port 25)... then configure assp to forward to port 125. (change the port # if you wish). Have assp listen on port 25, and also an alternate port if you need it for some customers, and it'll forward all connections to exim on port 125.
Then you need to make sure that 127.0.0.1 is in your /etc/alwaysrelay file... or you may have trouble with some email getting blocked.
As far as I can remember, I think that was all the changes I did to the system outside of assp... so just configure assp properly and you should be good to go! Use test mode at first while you build up your spam and notspam databases... and make sure that everything is correct! This may mean going through spam by hand to train assp for at least the first several days... depending on how much email you get. Follow the docs to set it up and search the ASSP forums if you get stuck and you shouldn't have any trouble.