I've seen an example at this address on how to add context menus by just dropping a key to the registry (in the example, we add one link to Notepad.exe for each file type *).
The example works fine, instantly. However, I don't understand why I can't reproduce the same with "excel.exe %1" under .xla.
Here is a screen of what I tried, initially, "shell" folder seems to be missing for each extension. Since I couldnt get any effect with "shellex", I added it... I can't see my menu :

Please keep in mind I am a registry newbie :)