[Martin v. Loewis wrote]
If you want to build extensions for this build using distutils, you need to ... 2. open an AMD64 retail shell ...
It might be possible to drop 2) some day, but finding the SDK from the registry is really tricky.
Look for: def find_platform_sdk_dir() here: http://cvs.sourceforge.net/viewcvs.py/pywin32/pywin32/setup.py?view=markup
That is the best code I know for doing that.