Missing Form Authentication provider For IIS 7 on Windows Server

I just test  asp.net web application on New windows IIS 7,
There is no Form Authentication. 
And there is no windows authentication default normally, and you should add in WWW Sevice\security subfolder.
But where is Form Authentication provider?
It under :  WWW Service\Application Development Features

Check : .Net Extensibleility, ASP , ASP.NET 

Form Authentication appeared.   (But which one is really needed?)