Hi,
I got it working after few steps. Here's how:
1. Get device's IP address. It should be printed on paper when
"(Cancel or Stop/Clear) -button" is held down for 5 secs. Did not work for me thought. Got the IP address from Samsung's "Easy Printer Manager" after I installed printer through USB. For me it was 169.254.112.195 ( maybe it is the default )
2. Change your MacBook to use the Samsung's own adhoc-WLAN. On OSX Wi-fi list there was SSID "sthrough" or similar ( can't remember anymore ) under "Device" -section.
3. Now connect to the Syncthrough Website http://169.254.112.195/sws/index.html ( use the IP you got in item 1. )
4. Login as admin ( password is in the installation guide or google, I guess I can't write it here )
5. Configure the Device's Network settings to use your own WLAN with correct SSID and password. You can choose your WLAN's SSID from the settings list ( good way to check that Samsung sees your WLAN )
6. Apply and http-connection is lost.
7. Add printer with OSX tools. If you can't find it Restart printer ( I did this just to be sure that it refreshes the connection to my WLAN )
Note: Not sure if you need to install Samsung's drivers from the installation disc. I did while troubleshooting.
Optional: Add the device's MAC address to your AirPort Extreme's allowed clients -list. ( If you use this feature )