Then u should try this app..
This app is very useful for me,it install any app in system...
This app has a build in file manager to install app in system pertition..
Or u can install any app from anywhere just u have to select system app installer
U even don't have to reboot phone for opening app.... and remember,not all app install in system,some app don't install in system....
Apk link - http://db.tt/fl1MOM46
Press thanks if it helps u..