My problem is that I'm trying now to use the 64 bit version now and CMake FindBoost script will only find the 32 bit version.

CMake correctly assume that the library files in the lib directory are the one to use, however it have no apparent way to

find if it is for 64 or 32 bit.

I don't know if i understood correctly, but you can set the library directory by hand, please refer to /usr/share/cmake-<version>/Modules/FindBoost.cmake, in particular the variable BOOST_LIBRARYDIR.

Regards,

Júlio.