mfeliu07 I have the same problem as you.
I've had live chat with Sprint twice, but no luck.
As other buddies say here, only Sprint can do it.
Or wait for the friend that achieved domestic unlock
to do the trick without Sprint (check out his post).
I tried Region Lock Away, region-free custom roms
but still no unlock screen. As far as I learned, the
sim card area of the device has to be unlocked
(not just the specific one you insert). It's very sad,
cause when I change network settings from cdma
to gsm, I can see my carrier, but can't register.