How to install spamassassin with directadmin custombuild

Let's assume CustomBuild is installed. 

We have to configure our options.conf and enable the spamassassin installation.

cd /usr/local/directadmin/custombuild
vi options.conf

Now we enable it under #mail options and save:

#Mail options
exim=yes
eximconf=no
clamav=no
spamassassin=yes
dovecot=yes
pigeonhole=no

Next we run update custombuild

./build update

BUT before we run ./build spamassassin we must first download all the requirements (as custombuild will not do this for us):

yum install spamassassin -y; yum -y erase spamassassin

So now that yum downloaded all the requirements we can now do the install. Though let's also update exim before we do this:

./build exim ; ./build spamassassin

And that should do it.