How to unlock the GSM simcard part of a Virgin mobile USA iPhone 4s?

I know the virgin network works of Sprint and is CDMA, but they LOCK the GSM capability of the phone. I want to use the phone outside of the US.
Virgin reps, do say that the GSM is locked and they can't and will not unlock the phone.
Is that even legal?
ALL other companies; Sprint, Verizon, AT&T, even Virgin Canada and Australia already allow this and Unlock the phones that customers have bought. But Virgin USA is giving its customers a hard time. Not a very nice way to treat a customer that paid FULL price for their phone.

You can unlock your phone for a fee using a third party unlocker service like cellunlocker.net or cellphoneunlocker.com.

I know, they suck. They charge you full and yet they won't unlock the phone so you can't use any other network other than Virgin USA. You can get the phone factory unlocked though. Mail this person (arghyle@rocketmail.com) who can help you get your phone factory unlocked.