Unlocking to a diff carrier ( galaxy nexus )

[Gatoppardo]

Hey, i have a Verizon Galaxy Nexus, im now trying to use it with a cdma carrier down in Mexico, y rooted succesfully , i saw superuser app and installed titanium bckp + root also. Now, please point me how can i unlock it to a diff carrier. ( something funny happened. when i started the registering process , after unlocking and rooting, it asked me to login to gmail accnt and offered to open verizon concierge, im sure it did not get rid of the verizon code all the way ).
Thank you guys in advance.