Possible to use .NET 4.0 assembly with Xamarin.iOS and Mono 3.0.x ?

Hi,

I would like to use a .NET 4.0 assembly in my project created with Xamarin.iOS.

Theorically, it's possible using Xamarin.iOS 6.3.x and Mono 3.0.x but when I create an empty project, reference the assembly and try to use it, I receive an error message that suggests the project uses Mono 2.x instead of Mono 3.x.

Is it possible to do what I want ?

Thanks in advance