According to a teardown of this device posted on youtube by mikeselectricstuff there are two curved lipo cells soldered in place in this device. You need to exercise care when working with lipo batteries so you dont accidentaly short them out. Perhaps you could try ebay and see if you can find the right type of curved cell there. Bending a normal lipo cell into the reqiured curve is not something you should try as this could make the cell prone to exploding/cathing on fire.
Hi, this might not be the best idea as bluray operates at a different wavelengt and as so will not be compatible with the rest of the control electronics in your existing dvd drive. What kind of computer do you have? Even a laptop should have fairly standard measurements for the bay that optic drives sit in.
It is impossible to determine from the picture but if you think about it the overlay where the button cap is held in place that should give you a pinpoint of where it is. I don't have any mac experience but plenty of other laptop experience so i cant say for certain but you are either looking for a tiny mechanical momentary switch or some interweaving pads directly under where the button is. It from experience I would say the first type is more common but I have seen both.