Change ContactSearchResultList Binding at runtime

Question

Im working with the Lync 2010 SDK and using a ContactSearchResultList bound to a ContactSearchInputBox. The Binding is done in the xaml-Definition like this:

<controls:ContactSearchResultList Name="contactSearchResultList1" ItemsSource="{Binding Results, ElementName=contactSearchInputBox1, Mode=OneWay}" />

Now I want to change the Binding to another ContactSearchInputBox at runtime. I tried it like this:

System.Windows.Data.Binding searchBinding = new System.Windows.Data.Binding();
searchBinding.Source = contactSearchInputBox2.Results;
contactSearchResultList1.SetBinding(ItemsControl.ItemsSourceProperty, searchBinding);

It does not throw any error, but the result list stays empty no matter what I do after I change the binding at runtime... Any ideas?