When I try to install by the setup.exe (my W8 was already installed), after some seconds, it says it can't find BootCamp64.msi and proposes the window to locate that file. It is not provided with the distribution of BootCamp 5.0.5033 (from the download page).
Nobody had this problem???
(Other point : no way to download more than half the drivers with the BootCamp Assistant...)