WIA (Windows Image Acquisition automation)--How to support the scanner
feature of duplex (2-sided) scanning?  I'm writing scanner support
code using the Fujitsu 4120-C as a testbed.  The scanner has a duplex
feature (I can activate it when using the Scanner and Camera Wizard)
but I do not know how one is intended to invoke such features
programatically using WIA automation.

Do not use the WIA driver from windows in stead use the twain drivers
provided by the manufacturers. The twain driver will support all the
features of your scanner. Also you will need to do into the control
panel and double click on scanners and camera. Right click on you
device and go to properties. You should be able to configure the
printer's features.

The best money I spent was for this ActiveX, NET DLL that makes it
easy for you to make your scanner jump and shake.
http://www.vintasoft.com/