(Sat 05:50 24/Nov/07)I don't know this unit specifically but usually a separate application is installed for OCR. Sometimes you have to choose to install the program during setup of the scanner drivers etc. To use it you can run the application and access the scanner from it.
Otherwise they have a scanner utility with a selection for OCR. The utility setup will have a place to configure the OCR program target. When you active OCR the scanner output is automatically fed to the OCR program.