If you want to compile your own packages for the CH3HNAS (even if you don’t want to use a single component of HFP), you can follow this guide. I wrote down all then steps I took to build the toolchain.

Install Debian
Install hfp utilities
Install packages
Create the scratchbox foreign toolchain (optional)
Create the initial hfp root filesystem
Create packages using buildroot
Create packages using scratchbox
Buildroot packages
Scratchbox packages

As I started out by using the SDK provided by Conceptronic, I also included the following instructies how to get this SDK compiled. However, I do not use this SDK at all in the HFP project:
Compiling the CH3HNAS-SDK package