Set awstats=0 and webalizer=1 in /usr/local/directadmin/conf/directadmin.conf.
I guess CustomBuild doesn't have a "remove" command for anything, because it would be very complicated to do it for some of the features and doing it for only a few of them can confuse the user.
You can, by the way, set "awstats=no" in options.conf, move /usr/bin/webalizer to /usr/bin/webalizer.old and run "./build webalizer". This will reinstall webalizer and set awstats=0 and webalizer=1 in /usr/local/directadmin/conf/directadmin.conf.