1. Adding license in Server Side :

• In order to add a license for a especific package, you need to create a .txt license file under path of a directory of package on ​http://download.osgeo.org/osgeo4w server, for example:

   svn someuser@download.osgeo.org   # log in into server 
  
   cd osgeo/download/osgeo4w/release/gdal/gdal-ecw
  
   touch gdal-ecw-1.9.1-0.txt        # you need to create a .txt license file
  
   echo "some terms of the restrictive package" > gdal-ecw-1.9.1-0.txt
   
  

2. Steps for Testing extend Features of OSGeo4W :

• Before you follow this steps you should do all configurations and build the setup.exe at http://trac.osgeo.org/osgeo4w/wiki/SetupDevelopment
• make the following:

    Download "setup.override.ini"  file  from [http://trac.osgeo.org/osgeo4w/browser] in the root of your local directory 'C:\' 
    ./setup.exe  # run it.
   
    
  

• Choose the next option: Advance Install > Install from internet > Root Directory > Local package directory > Direct connection
• Choose a restrictive package for example 'gdal-mrsid' or 'gdal-ecw' or both, you should to choose these because I just created a file for each one in 'download.osgeo.org' server. If you choose another restrictive package setup.exe will raise an error, and choose another normal package for example: 'gdal-java'.
• Setup will download the license file from remote server into your local directory "Local Package Directory" , you can see it if you want.
• Next step setup.exe will load the file license into a window and it will show you.