I've followed the tutorial written by AlpineMan but I can't activate the device since I don't have access to Sprint network in Europe. According to the tutorial activation should also be possible over WiFi, but I had no luck.
My question is: Do you need to have access to the Sprint network in order to activate the phone and are there some negative consequences if the device is not activated?
Thx in advance.

I didn't find the right solution from the Internet.

-References
-http://forum.gsmhosting.com/vbb/f801/can-you-activate-sprint-s4-europe-2214849/

-Product Design Video