While technically it would be possible for us to install Zend Optimizer on a UPipe server, we have chosen not to because of the potential for unforeseen problems with various aspects of the Plesk Server Administrator interface. Also, we're unsure what impact installing Zend Optimizer would have on the resources of a heavily used server like the UPipe server. We try to avoid experimenting on production servers as much as possible for uptime and stability reasons.
At present, if you really need Zend Optimizer your best option is to order a VPS hosting account and install the Zend Optimizer application template.