I guess blpython.cpp/.h is compiled into blpython.dll, you shouldn't need the source.
Behaviours are in cs/data/library/blpython, but i don't think it's something to worry about.
C:\Python25\ in PATH
PYTHON set to C:\Python25\python.exe
PYTHONPATH set to C:\Python25\Lib;%CRYSTAL%;%CEL%
Set pythonpath after crystal and cel, these %% things should change into real paths.
Use celstart.exe (copy maps, maybe something more, into cel) -- pycelstart.py resets pythonpath.
Try also adding map file to the pythonpath (e.g. add C:\crystal\maps\lookat.zip, after ';').
I've been compiling 1.2rc2 in parallel, so maybe i've actually borrowed something?
Now under ubuntu so i can't verify all of this, sorry for that.
It should be easier to first get this working standalone and then try with blender.
As a last resort change behaviour layer to xml based (within blender blxml under celexport), never had any problems with that.