Nope sorry, i had a clio before and so was told I couldn't put a bike carrier on the boot. So I got a couple of roof mounted carriers.
When I then got my Megane I just got new bars... not cheep though... For the two bike carriers I got them from a website called skidrive for about £55 each for thule carriers.
Got my thule aero bars from there too for about £125 for the whole kit...
I have seen some people who have bike carriers on the boot door though so think it is possible... the best manufacturer of boot mounted carrier is a company called Saris... they do one called a "bones" which is meant to be excellent...
Hope you manage to sort something out