Update: I did it successfully. It was rather easy. All one needs is the smallest flat-head screw driver... the one that is available in a Dollar Store as a set with bunch of other star-head and flat-head screw drivers. After opening the back panel, drove the screw diver on the edge where rubber and aluminium panel meet and Voila... it came up and sat over the edge... Additionally, I applied super glue to keep it there. However, my advise is, if one has patience and it done all right with just the screw driver enabling rubber sleeve to fit on to aluminum panel, just leave it that way. This gets the job done as neat as the factory supplied one when the MackBook was new. The cost... None.... And Apple people were trying to scare me with all the big and shallow talks of warranty void and etc.... and huge sum of money in case the back panel needed replacement.