Enable Virtual buttons on Android ICS
You can Enable Virtual buttons on Any Android Ice Cream Sandwich ROM (Android 4.0.x), with a simple trick.
You must follow the instructions below very carefully in order to get Virtual buttons on ICS.
Step 1: Use any: ES File explorer or Root explorer to copy system > framework > framework-res.apk to PC.
Step 2: Keep a backup of the original APK & Decompile the copied APK using APK Tool. APK Tool 1.4.3 would work fine.
Step 3: Open /res/values/bools.xml using a text editor, find config_showNavigationBar and set its value to true.
Step 4: (Optional) Optionally you can turn off backlight for your hardware capacitive buttons. To do this, edit arrays.xml. Search for config_autoBrightnessButtonBacklightValues and set all item values to ’0′ (i.e.zero).
Step 5: To avoid keyboard overlapping problem, you need to adjust the dimensions for the virtual buttons.Open dimens.xml, find navigation_bar_height and edit its value to something which suits you best. 37.0dip should be good.
Step 6: Compile the APK using aapt. Copy the modified APK back to system > framework.
You should now have enabled onscreen Virtual soft button for back, home and multitasking. Capacitive buttons will be disabled for some users, for others, they would continue to work.