Follow these steps while logged in as root:
1. Configure the /usr/local/directadmin/custombuild/options.conf and change the settings to whatever you need.
2. If you want something specific enabled, change around the configuration files in /usr/local/directadmin/custombuild/configure
3. Run ./build all or ./build apache or ./build php from /usr/local/directadmin/custombuild directory.