First things first! I am using Ubuntu Mate on 15.04. I installed Qgis and SAGA via the http://ppa.launchpad.net/ubuntugis/ubuntugis-unstable/ubuntu packages. So I use QGIS 2.12 and SAGA 2.1.4.
I wanted to use the cluster analysis for grid tool, available in the SAGA-toolbox and I couldn't find it. It should be under shapes->table but I checked and the entire table-tools are missing. Others might be missing too (Qgis is showing 235 SAGA-tools). The ones which are there are fully functionable.
In the official SAGA-programm the tool is visible though. So how can I port the missing tools into QGIS?