I stumbled upon this article and followed all steps. But pyDev won't see my flask extensions and that's really annoying. There's only one thing (and I think this is the key):
Touch /site-packages/flaskext/__init__.py
Touch is a unix util I think. Is there an equivalent to this on Windows?
The Eclipse uses static analysis of modules by default. flask.ext builds import list dynamically. To force dynamic analysis using Python shell add flask.ext to forced builtins list.
Go to Preferences -> PyDev -> Interpreters -> Python Interpreter. Select your interpreter, go to Forced Builtins tab. Click New... and enter flask.ext.
This requires PyDev to forcefully analyze module through a shell.
For more details see PyDev manual.