They DO register them, just not under those color names.
Smokey black is just black w/ a cream gene, so they'd just be registered as black. And personally that is how I think they should be registered, the cream doesn't affect the color, it would be like registering chestnut/sorrel that carries agouti w/ some special name. Sometimes I think things are made more complicated then they need to be.
Don't know on the smokey cream, I'm guessing they register then as perlino, cremello and perlino are the better known double delutes. Many people can't tell the difference in the colors anyway, and I'm guessing they tend to go more on visual then on genetics.