edit the buildout.cfg for your site:

cd .../zeocluster
vi buildout.cfg

the changes being:

[buildout]

eggs =
    Products.PloneFlashUpload
    example_com
    Products.Quills
    Products.PloneArticle

zcml =
    example_com

develop =
    src/example_com

[productdistros]
recipe = plone.recipe.distros
urls =
    http://plone.org/products/simpleblog/releases/3.0/simpleblog-3-0-beta1-tar.gz
nested-packages =
version-suffix-packages =

In this case example_com references .../zeocluster/src/example_com

The rebuild and restart Plone:

./bin/buildout
./bin/plonectl stop
./bin/plonectl start

Then navigate to the site; Site Setup; Add-on Products and install anything required.