If you have a working, that is, not disabled internal GPS, you shouldn't need BBMaps to start the GPS. I'm not familiar with the Power Vision Pack, but if Sprint is disabling your GPS, your only option may be an external bluetooth puck. That's what Verizon users use.
That sounds like what Verizon does. The GPS is not disabled in any setting you can see. It just doesn't work unless you subscribe to their VZNav service. And then it only works with VZNav. They don't permit its use with any 3rd party apps.