install Zend Optimizer/Guard, and/or Ioncube on Directadmin
1. Zend
cd /usr/local/directadmin/custombuild
./build set zend yes
./build zend
./build set zend yes
./build zend
cd /usr/local/directadmin/custombuild
./build set ioncube yes
./build ioncube
./build set ioncube yes
./build ioncube