Sorting content in list-of-lists on UI

Hi,

Hopefully I'm missing something simple. I have a collection of collections, and I'd like to display the inner collection as a sorted list. From what I've researched, the best way to do that is to sort the collection on the view. However, I'm having trouble getting the binding correct. 

From what I've seen, I should be using a CollectionViewSource to specify the sorting mechanism. The examples all have a named CollectionViewSource, but that doesn't work in my case since the collections are dynamic. Here's what I have so far:

<ItemsControl ItemsSource="{Binding ElementName=ctlMainWindow, Path=MainCollection}"><ItemsControl.ItemTemplate>                        <ItemContainerTemplate><StackPanel Orientation="Horizontal"><Label Content="{Binding Path=Key, Converter={StaticResource EnumToImageConverter}}"
                                       Height="36"
                                       VerticalAlignment="Center"
                                       Width="36"/><ListBox HorizontalAlignment="Center">
<ListBox.ItemsSource><CompositeCollection><CollectionViewSource Source="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListView}}, Path=Value}"/></CompositeCollection></ListBox.ItemsSource><ListBox.ItemsPanel><ItemsPanelTemplate><StackPanel Orientation="Horizontal"/></ItemsPanelTemplate></ListBox.ItemsPanel><ListBox.ItemTemplate><ItemContainerTemplate><Label Margin="2" 
                                                    Height="54"
                                                    Content="{Binding Path=.Image}"/></ItemContainerTemplate></ListBox.ItemTemplate></ListBox></StackPanel></ItemContainerTemplate></ItemsControl.ItemTemplate></ItemsControl>

When I bind the top Listbox using ItemsSource={Binding Path=Value}, everything works as expected (though it's not sorted). Hopefully I'm just missing something simple, but I can't figure it out. Any help would be appreciated. Thanks!

-Terry