Installing CUDA 7.5 on Debian with packaged bumblebee

My laptop, which runs Debian Jessie, has switchable graphics cards (Intel + NVIDIA GT 520M), and for this I have installed Bumblebee & Primus, which depends on the NVIDIA driver in the package manager. Now I need to install CUDA 7.5, and therefore need a more recent driver (even the backports one is too old). However, to install the one bundled with CUDA, I need to remove the one from the package manager, which is not allowed due to the dependency. How can I make the packaged bumblebee work while using a non packaged driver?