1.Download Zend Optimizer from www.zend.com and follow the installation procedure.
2.Once the installation is complete, create tar file using following command.
# tar cf virtDomain.tar /usr/local/Zend   (Assuming that Zend has been installed at default location - /usr/local/Zend)
3.Copy this tarball to /etc/appliance/customization
4.Download the attached custom script named virtDomain.sh and upload the same to /etc/appliance/customization
5.Download the attached custom script named editVirtDomain.sh and upload the same to /etc/appliance/customization

Note : you need to replace Zend Extension part with one copied from /usr/local/Zend/etc/php.ini in the attached scripts.
6.chmod both script to 755

Now all new domain created on server with any security level will be Zend enabled. If you want existing domain with high security to be zend enabled then you just need to re-save the site from Webppliance.