Facing the same pro here try http://www.3gnewsroom.com/phorum-3.4.8a/read.php?f=39&i=1&t=1 maybe you will find it haelpful, it didnt work on my one
Apparently you can get it unlocked 'officially' for about £115 but don't ask me where. The V version has improved connectivity problems with this phone but has rendered it unlockable at the same time - atleast done cheaply. Flog it on ebay and get some of your money back if you don't want it. Three network is only good if you use over £15 a month normally on calls. I've ordered the Nokia 7600 which also uses three but is unlockable and has similar features to the NEC and is more reliable.
i found this browsing around the web,dont no if its ok or not,might be worth a try Unlock your NEC e616v | Firmware acpu:a125.56.07 ccpu:c623.r0v (With threes (3g) usimcard inserted) Press: #4960*49273408# (OBS! nothings happen) Press: *4960*49273408*49273408# ("simcard lock on" in the display) (Change to your 2g simcard, restart the phone and press your pin1) Press "down" (with the pad) and write 49273408 and then OK Press: #4960*49273408# (OBS! nothings happen ) Press: *4960*49273408*49273408# ("Simcard lock on " in the display) (Change to your 3g card (3) and press your pin1) Press down with the pad press 49273408 and then OK Change to your 2g simcard same as above hope it works for you or anyone else.
Huh - I have tried all sorts of #* versions, still no good if i enter my 2g sim then it'll display "insert valid Usim card" I wonn't give up... yet so still keeping my ear to the ground! *Little bird (my friend who's smart about smartphones) told me that there is soon available software for those fones, so fingers crossed