Here is a link to an older post that might help.
Plus, if you go through the users manual, it should have steps on how to configure the Scan To PC, once that is setup, you should be able to disable the USB port, Which might cause a problem with Print from USB.
I have Xerox WorkCentre 3325 - work perfect. By default machine scan to USB.
Is there a chance to set it up by default to scan to Local PC ? Or hide scan to USB ?