Linux Mint duplex driver for Samsung M2070

I'm trying to print duplex on my Samsung M2070 Printer. I installed the driver from the Samsung website with the provided install.sh and then added the printer to the system in the Printers section of the System Preferences. I see the Printer in LibreOffice Writer, and I can print with it, but there isn't a duplex function in the print window (On Win7 there is a Checkbox). Do you have any ideas? **Update** I clicked on "Print" in LibreOffice and then "Properties" and "Paper". I saw the disabled duplex combobox. I thought on a driver issue, so i went to CUPS administration to check my driver. It wrote, that my driver is able to print duplex.