Concerning _xmlplus, python as the following hack:
we are not suppose to import _xmlplus but xml instead and in the __init__.py of xml _xmlplus is binded (sys.modules[__name__] = _xmlplus)
So something like "from xml import xpath" actually looks for xpath in _xmlplus package.
Pydev (1.7) gives an error: Unresolved import : xpath while it is actually valid (because it is a module in _xmlplus)
See http://www.amk.ca/conceit/xmlplus.html for the hack explanation