framework-check

How to require .NET 3.5 framework?

My client-side app is built using .NET 3.5, in fact, I want to require that the user has it installed. Before I even start the app, I want to make sure that the framework is present on the box. I tried to use the <requiredRuntime version="v3.5..."/> but it seems that the underlying code can't really tell between .net 2 and .net 3.5 ...