Ok, I will see how far I can go and then I share on GitHub.
Once you arrive at a point where you get stuck and seek practical assistance, sharing your branch would be most effective way to allow us reproducing your problem.
Ok, If I find something relevant that I needed to do that is not covered or clear enough here I will let you know.
Is the Section 5.3 "Build system" of the forthcoming documentation [1] able to clear things up? If not, I am keen to know what information you find missing.
Please refer to Section 5.5.2. "Development practice" of the soon-to-be-published documentation [1].
[1] http://genode.org/files/53bcb8e33fe6602fed25edc3c7b922c5/manual-2015-04-27.p...