From memory (I try to provide something more detailed at the weekend, but cannot promise that I manage to write it down):

You should be able to download the sources including the debian dir from bokomoko.de (just use deb-src in sources.list). This should build out of the box on the x86 target. On the armel target, one package does not build, because a binary fails on qemu. This is a know problem in the armel build setup inside scratchbox (and also the reason, why navit is not in the extra repository). Fortunately, it is the navit_data package which is architecture independent and I can simply take the package from the x86 build. Also make sure that you have freetype from CSSU or my libfreetype-navit package.

Hope that helps somewhat,
Rainer