Hi olivier1,
Our Country Nepal is devastated due to the massive EarthQuake so we are very much sorry for late reply.
We recommended not to change the code because if you change the code then while updating to our new version all your customisation code will be lost. So better make child theme and first unhook the functions and the edit the code.
http://codex.wordpress.org/Child_Themes
The file is inside theme folder(ultimate)-> inc -> structure-> content-extension.php. There is a function for single.php so you may edit the code inside this page.
Thank you!