Binding Aar not working

Hi,

Using Xamarin studio, I've followed these explanations

https://developer.xamarin.com/guides/android/advanced_topics/binding-a-java-library/binding-an-aar/

Once the library is built and referenced in an android project, when I use the assembly browser to see the classes, methods, and so on, all I
got is :

AarBinding

Resources

AndroidLibraryProjects.zip

I've use the aar provided by the link above.

so, what could explain the fact that the library is not good or doesn't show anything like if the binding process failed ?

Thanks, this is really important to me to get an answer to this question !!!