I've just installed this printer and enabled - everything is working on airprint with my iPad2, iPad Air, Macbook and Mac Mini.
The trick was to connect to the printer's wireless network directly (the direct connect box must be clicked when you're setting up with a USB connection) first. The next time I tried to find the airprint printer, it was there.
There is a password associated to the printer's direct connect network as well (setup utility gives you this). I'm guessing that once it's in the keychain for the device, it can find it and connect to it.
Anyway - this should solve the mystery. It's all installed and working. I didn't have to do a firmware upgrade (not available except as a windows.exe file), but I did install the latest driver off of the support community. I couldn't get the scanner to work until the driver was up to date.
I'm running OSX 10.9, printer is Samsung SCX-3405FW, iPad software is latest on both iPads.