Yep Gina has been replaced with another credential system called ICredentialProvider
It seems very tricky (and not very documented) but I found some Microsoft sources for you :
http://msdn.microsoft.com/en-us/magazine/cc163489.aspx
and
http://msdn.microsoft.com/en-us/library/bb776042%28v=vs.85%29.aspx
Hope this helps you but requires some programming with the API. And, please, don't forget to score.
Cheers