Hi @koeny, thanks for reaching out. Whilst unfortunately Tobii do not provide the software to achieving what you are looking for, there is a project I am aware of that allows you to create gazeable areas on screen to perform custom tasks that might be of use.
It recently restarted development, so I am not sure about ET5 support, but by all means try out the demo and let us know how you get on.
Their website @ http://iris.xcessity.at/index.php Best Wishes.