Forget about site.zcml; just create an small add-on package that has (1) a directory for your static resources, (2) a configure.zcml file using a browser:resourceDirectory declaration. Put your add-on in source control somewhere.
Your package should set up the following structure (assumes UNIX, you can easily translate this to Windows equivalents as you see fit, rename package appropriately):
~/my-buildout $ cd src
~/my-buildout/src $ mkdir -p myorg.packagename/myorg/packagename/static
~/my-buildout/src $ cd myorg.packagename
~/my-buildout/src/myorg.packagename $ vim setup.py # edit as needed
... # see http://docs.python.org/2/distutils/setupscript.html
~/my-buildout/src/myorg.packagename $ vim myorg/__init__.py
Make your namespace package work (in myorg/__init__.py):
try:
__import__('pkg_resources').declare_namespace(__name__)
except ImportError:
from pkgutil import extend_path
__path__ = extend_path(__path__, __name__)
Other boilerplate:
~/my-buildout/src/myorg.packagename $ echo "#" > myorg/packagename/__init__.py
~/my-buildout/src/myorg.packagename $ vim myorg/packagename/configure.zcml
Your configure.zcml should look like:
<configure
xmlns="http://namespaces.zope.org/zope"
xmlns:browser="http://namespaces.zope.org/browser">
<browser:resourceDirectory
name="MYPROJECTNAME"
directory="static"
/>
</configure>
Installing add-ons is well-documented for Plone, so I am omitting description of that.