Egg files not found in path Follow

I've got a somewhat complex project structure, and PyCharm isn't picking up any of my egg dependencies.

The project layout is roughly:

buildout.cfg
setup.py
eggs/
develop-eggs/
submodule1/
  buildout.cfg
  setup.py
submodule2/
  buildout.cfg
  setup.py
bin/ 
  python
env/
  lib/
    python2.7

prettyPrint();
With the master buildout file building each of the submodules as develop eggs (in /develop-eggs/), and installing their dependencies in /eggs/.

In my PyCharm project interpreter's path I have:

file:///home/paul/env/lib/python2.7
file:///home/paul/env/lib/python2.7/lib-dynload
file:///usr/lib/python2.7
file:///usr/lib/python2.7/plat-linux2
file:///usr/lib/python2.7/lib-tk
file:///home/paul/env/local/lib/python2.7/site-packages
file:///home/paul/env/lib/python2.7/site-packages
file:///home/paul/submodule1/src
file:///home/paul/submodule2/src
file:///home/paul/develop-eggs
file:///home/paul/eggs
jar:///home/paul/eggs/netaddr-0.7.10-py2.7.egg!/

prettyPrint();
There are two issues here:

1) In order to get imports from the submodules, I've had to manually reference each submoduleX/src directory. That's a shame, since I'm using develop eggs, so I'd hope to be able to just point to the develop-eggs directory and automatically pick up all the submodules in a single step.

2) More seriously, I can't get egg references working at all; in this case I've included netaddr as an example. This module is specified as a dependency in my submodules' buildout.cfg, and so it's deployed into the /eggs directory. But adding the /eggs directory to the path has not caused PyCharm to locate the module (nor has explicitly referencing the egg itself).

I'm obviously missing something fundamental about how PyCharm handles imports; anyone got suggestions for debugging steps, or solutions to try?

Thanks,
Paul