Use different user directories for different Jdeveloper versions

In my system I have 4 jdev versions installed , jdev 11.1.1.7 , jdev 11.1.1.9 , jdev 12.1.3 and jdev 12.1.3

by default when i create a new application or project it is creating under the directory C:\JDeveloper\mywork

this is causing too much confusions for me in opening up the projects.

First create user environment variable's

JDEV1117_USER_HOME=d:\myjdevwork\jdev1117

JDEV1119_USER_HOME=d:\myjdevwork\jdev1119

JDEV1213_USER_HOME=d:\myjdevwork\jdev1213

JDEV1221_USER_HOME=d:\myjdevwork\jdev1221

Open the file D:\jdev1117\jdeveloper\jdev\bin\jdev.boot

and comment the variable ide.user.dir.var and add the following 

#ide.user.dir.var = JDEV_USER_HOME,JDEV_USER_DIR

ide.user.dir.var = JDEV1117_USER_HOME

Do the same for jdev 12.1.3 

D:\soa12cqs\jdeveloper\jdev\bin\jdev.boot

#ide.user.dir.var = JDEV_USER_HOME,JDEV_USER_DIR

ide.user.dir.var = JDEV1213_USER_HOME