I just tried this myself, but couldn't get it working.
However, when I downloaded your zip file and used your folder it worked.
I don't know where the files "test_mod.scpt" and "test_mod.sh" are comming from, but I guess that was the problem XD. If not I most likely missed something, well, doesn't matter right now.
Anyways ... I found something regarding the "resources.cfg". I don't know if this is commonly know by now, but it seems like the folders that are included first in the file are preferred.
Let me make this as clear as possible:
I installed the flashlight mod into the "test_mod" folder, but I still got the normal lantern in the game.
At first the model was working, but the sounds didn't, so I tested around a bit, untill both didn't work anymore XD.
Then I found the solution: I changed the folder order in the "resources.cfg" from ...
<Directory Path="/models" AddSubDirs="true" />
<Directory Path="/test_mod/models" AddSubDirs="true" />
... to ...
<Directory Path="/test_mod/models" AddSubDirs="true" />
<Directory Path="/models" AddSubDirs="true" />
So, what I want to say basically is:
The folders that are meant to overwrite standard files have to be included first.
Maybe I just missed it, but I think you haven't mentioned that in your tutorial. You might want to add it.