Broke up Express app into submodules - now my custom "x-powered-by" does not work

I watched the tutorial here:

.. and got inspired to break up my ever-growing application into distinct modules. The high level structure is as follows (some parts deleted for brevity):

server.js:

var express = require('express')
  , orgs = require('./lib/orgs');

var app = express();

app.configure(function () {
  app.disable('x-powered-by');
  app.use(orgs);
});

http.createServer(app).listen(app.get('port'), function () {
    console.log("Express server listening on port " + app.get('port'));
});

lib/orgs/index.js

var express = require("express")
  , app = module.exports = express()

It works great. However, I have a small problem which may lead to bigger problems going forward. When I structure my app this way (e.g. having express 'submodules'), the x-powered-by is not disabled, which leads me to believe that all app config stuff is not read as well. I have tried to place the disable message before and after calling the orgs submodule.

Can someone please help me understand this? Thanks