escudito,
I also have a SCX-3405W with a computer running Fedora 19. I am unable to get scanning to function, however. I am sure I am doing something incorrectly. I did successfully install splix, and when I go into printer settings and add a printer, it detects a "SCX-3400-Series", for which the model is a Samsung SCX-3200, but does not have the 2.0.0 as you indicated.
Under this configuration, I can print, but not scan. The "sane-find-scanner" command DOES returns the following result:
found USB scanner (vendor=0x04e8, product=0x344f) at libusb:003:004
However, the simple-scan program does not work. If I try to scan anything, it just says that the scan failed because no scanners are available. If you can help me get this working, I would really appreciate it! :)