Default Stock Camera/ Gallery ( Help Please)

Hi,

With the help of various tutorials in the XDA forum I have successfully ported MIUI V5 with root access for my device . But I want to retain the stock camera and gallery application. The stock camera is somehow embedded in the gallery apk(there is no separate apk for camera). When I try to install gallery.apk in the ported rom it doesn't get installed.
I tried flashing the stock gallery.apk directly too(by putting in the system/app folder and then flashing the rom) but it didn't work. I have also tried replacing libcam*.so files from system/lib, but it didn't help either.

Appreciate your help in this regard. My device is a Mediatek 6589T(Karbonn Titanium X)