In my Visual Studio installation there were three folders that contained *.tmLanguage files
I tried it in each of them, and in one of them, once you exit from Visual Studio and start it again, it worked fine
Antonio,
I allways close the Visual Studio before copy files, but don't Works for me 
To work, "Harbour" have to appear in the Tools/Options/Text Editor list?
Vilian,
Where are your *.tmLanguage files placed ?
In what path ?
Antonio,
Here is it :
C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\Extensions\0pmyoiw4.hzh\Starterkit\Extensions\Harbour\Syntaxes
Mine is here:
c:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\Extensions\1kztsa3m.wi0\Starterkit\Extensions\Harbour\Syntaxes\Harbour.tmLanguage
They are basicly the same, but the mine don't work
What I'm doing wrong ? I need set anything more ?
Vilian,
No, thats enough.
Try to modify an existing tmLanguage file and see if your changes are used from Visual Studio
