Default sprint galaxy S4 can't connect with Gsm sim

hi i live in Europe and i want only Gsm phone i don't care about cdwa or sprint phone has 4.3 android MDC i made the unlock i found with galaxy s4 flashed and the only thing i manage was to go from ''invalid sim'' to sim connected without network no network.i have root the phone and now running cyanogen 11 but every time i try to choose GSM network i get ''''.i had also try service menu unlock without success.any idea how can i get it work???should i keep sprint kernel and try to boot samsung i9505 rom??thanks all of you in advance!!!