Installing extensions (Windows )

Hey,

     I have my rapidminer_server folder in windows machine on path "D:\Rapidminner_server" and created a folder plugins ("\Rapidminner_server\plugins") to store extensions. In Rapidminer server "com.rapidanalytics.plugindir" is empty so i set path as above but it is still not loading extension to the server. 

Any help will be appriciated