Why can't I see a v3.5 setting at the Application Pool in IIS?

The ASP.NET 3.5 Framework is the ASP.NET 2.0 Framework with some new compiler tricks. Therefore a 3.5 web site is going to use the v2.0 setting at the Application Pool configurations in IIS. The 4.0 Framework is a standalone version and uses the v4.0 setting at the Application Pool configurations.