OK. I found a solution for generally installing any package.
From this link [
http://www.lfd.uci.edu/~gohlke/pythonlibs ] download the required .whl file and place the file in [ C:\Program Files\WorldViz\Vizard5\bin\Scripts\ ].
Run Vizard as Adminstrator and execute python script at [ C:\Program Files\WorldViz\Vizard5\bin\Scripts\pip-script.py ] with arguments "install <name of your .whl file>"