Real-Time Kernel for RaspberryPi (Take II)

After unsuccessful attempt to compile Archlinux-rt kernel,
I encountered a very good guide describing how to compile a Debian Linux-rt kernel with Xenomai for the RaspberryPi. and a completing page for creating the RPI image.
I can't say I understand it completely, but I managed to combine to two guides and compile my own RaspberryPi Linux-rt kernel.

I'm sure some of the steps are missing and things change very quickly (e.g. links, kernel versions and patches) so anyone following my steps should take that into consideration and adapt to changes.

I started by installing a fresh Debian 32bit x86 on a virtual box.
Follow the picnc guides but remember to adapt the patches and kernel version differences.

I'll try to redo the process and give here a complete guide at a later stage.