I have a new 3345 which has the duplex automatic document feeder but the "Xerox Print and Scan Experience" software doesn't seem to have an option to scan in duplex mode!
The "Print To" option on the printer itself allows you to select duplex scanning but I could not get SMB or SMTP to work. I can get things to work if I install an FTP server on my computer but that seems a complicated solution?
Can you duplex scan from the "Xerox Print and Scan" software with the 3345? That software has all the nice scanning options I need - just missing the main one.