Hi Marco,
1) You're right, that namespace was wrong, and it was exactly because I didn't have the planner namespace when I uploaded the learning-content package to the cvs, I've fixed this in the cvs, I updated the learning-content-callback-procs.*
2) Chat is not fully supported by the Planner now, I need to create an extra script to patch all the chat files and set some conditions to make it work only when chat is installed.
Whenever I get more time I will look into all the fixes/improvements you have pointed out.