SHA256.Create

[zvenny]

Experimenting with the SHA256 class and now struggling with the Create method overload that takes the hashname as a parameter

SHA256 alg1 = SHA256.Create(); // returns a default SHA256Managed instance
SHA256 alg2 = new SHA256Cng(); // returns a SHA256Cng instance
SHA256 alg3 = SHA256.Create("SHA256Cng"); //always returns null

Guess I'm not passing a correct string !?!?
Any suggestions ?