Phone [Help] Need Help With Navigation Bar

Hello everyone,

So basically I own the phone Vodafone Smart Mini (V875) and it's running stock jelly bean 4.1.1, stock recovery, stock kernel but i rooted it and installed busy box

So, i wanted to have the Nexus 4 Navigation bar so i went to /custpack/build.prop and changed qemu.hw.mainkeys=1 to qemu.hw.mainkeys=0 which was supposed to do the trick but that didn't do anything, i made the changes, saved and rebooted but nothing happened

The device has Mtk 6575 processor so that's why the actual build.prop is in /custpack/ not in /system/ , so I was hopping someone helps me with this since I really want that navigation bar but I've been trying everything but nothing works

Also I attached my build.prop below if you want to take a look at it
Attached Files
File Type: 7z build.7z - [Click for QR Code] (3.5 KB, 5 views)
Device : Vodafone 858

Android Version : 4.0.4

Rom : CM9.1

Kernel : CM9.1 Stock Kernel

Overclock Settings : Min. CPU : 633MHZ - Max. CPU : 652MHZ - Governor : PERFORMANCE - Scheduler : NOOP

Launcher : Apex Launcher

Extras : -EXT 4 Second SDCARD Partition - Swap Partition in use - Touchwiz Theme Installed