Binding a Android Library Project, Class not visible

I'm trying to create my own copy of the (deprecated)slidingdrawer as it is suggested in the google documentation. For that I created a Android Library Project (https://github.com/suizo12/SlidingDrawer) and followed the instructions "Android Library Projects" (http://docs.xamarin.com/guides/android/advanced_topics/java_integration_overview/binding_a_java_library_(.jar)/).

Building the project, after creating a new one and referring to the binded one was no problem at all. My problem is, that I'm not able to access the class from the Android Library Project.

The strange thing about this is, that creating an axml file like this did work.

<com.suizo.slidingdrawer.CustomSlidingDrawer 
    android:id="@+id/HomeDrawer"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    custom:content="@+id/content"
    custom:handle="@+id/handle"
    android:rotation="180">

<LinearLayout
    android:id="@+id/content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#99000000"
    android:orientation="vertical" />

<LinearLayout
    android:id="@+id/handle"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:rotation="180">

<Button
      android:id="@+id/Button"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"          
      android:gravity="top|center_horizontal"
      android:shadowColor="#000000"
      android:shadowDx="1"
      android:shadowDy="1"
      android:shadowRadius="4"
      android:text="Text"
      android:textColor="#e7ecec"
      android:textSize="14sp" />
</LinearLayout>

</com.suizo.slidingdrawer.CustomSlidingDrawer>

and while debugging the object slidingDrawer has the type "com.suizo.CustomSlidingDrawer", but I'm not able to create a reference to it.

var slidingDrawer = FindViewById(Resource.Id.HomeDrawer);

Opening the dll in Visual Studio with the object browser doesn't show any class.

Has any one a idea why I'm not able to see the class?