[Geany] Adding a new file type?

[Laszlo Nagy]

   Hello,

Next thing I would like to do is to add some syntax coloring.

I have copied these:

/usr/share/geany/filetype_extensions.conf to 
~/.config/geany/filetype_extensions.conf
/usr/share/geany/filetypes.c to ~/.config/geany/filedefs/filetypes.ssdl

Then under [extensions] section of  
~/.config/geany/filetype_extensions.conf I have added this line:

SSDL=*.ssdl;


Then I have restarted Geany, but the new file type is not recognized, 
and it is not listed in the menu. (If I select the "C" source code file 
type manually then the file will have different colors.)

What else do I need to do to recognize the new format?

Thanks,

   Laszlo