1) Extract ISO content on HD
2) Replace install.jar in Matlab 2015b\x64\java\jar\ by provided file
You can create ISO again with modified content also
3) Install using any file installation key, e.g.: 11111111111111111111
and do not activate !
3) Replace MATLAB\R2015b\bin\win64\libmwservices.dll by provided file
4) Start MATLAB and give him a provided license file