Custom Control with BindableProperty.

Have a custom control that contains this property.

public static readonly BindableProperty ItemsSourceProperty =
BindableProperty.Create("ItemsSource", typeof(IEnumerable), typeof(HorizontalScrollView), default(IEnumerable),);

    public IEnumerable ItemsSource
    {
        get { return (IEnumerable)GetValue(ItemsSourceProperty); }
        set { SetValue(ItemsSourceProperty, value); }
    }

I bind to this property with via a webservice. Everything binds correctly unless I call my webservice with the await keyword then my binding does not work.

calling the webservice like this works
return cvClient.LogIn(lvLoginRequest);

calling the webservice like this does not
return await cvClient.LogIn(lvLoginRequest);

Thanks in advance.