Maybe I got your question wrong, but you can easily compile all needed libs by yourself. Just download the source and compile it inside the scratchbox environment.
This is the way I do it:
1. Often I come across a missing library when doing a ./configure for a wanted app. I look up the (Debian) package name of that lib via
Code:
apt-cache search xyz
2. Afterwards I download its source:
Code:
apt-get source libxyz-dev
3. Then I compile and install it into the scratchbox environment ("make", "make install" etc.)
4. After successfully installing the needed lib I continue with the compilation process of the wanted app. The dep-helpers ("lib-gen.sh") will then automatically find the new library.
Hope this helps.