toolkit:ExpanderView in Listbox - xaml

Question

I have troubles with binding data to a Listbox to dynamically create ExpanderView.
I have used Listboxes in my Code before, so I'm not sure if the binding is really the problem. Am I setting the contents of ExpanderView wrong?
My Code so far in XAML:
<ListBox x:Name="Newsticker_Listbox">
<ListBox.ItemTemplate>
<DataTemplate>
<toolkit:ExpanderView Header="{Binding}" Expander="{Binding}" ItemsSource="{Binding}"
HeaderTemplate="{StaticResource CustomHeaderTemplate}"
ExpanderTemplate="{StaticResource CustomExpanderTemplate}"
ItemTemplate="{StaticResource CustomItemTemplate}" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
the Templates:
<!--newsfeed templates-->
<phone:PhoneApplicationPage.Resources>
<DataTemplate x:Key="CustomHeaderTemplate">
<TextBlock Text="{Binding Title}" />
</DataTemplate>
<DataTemplate x:Key="CustomExpanderTemplate">
<Image Source="{Binding Subtitle}" />
</DataTemplate>
<DataTemplate x:Key="CustomItemTemplate">
<TextBlock Text="{Binding Title}" />
</DataTemplate>
</phone:PhoneApplicationPage.Resources>
I'm binding with
ObservableCollection<news> newslist = new ObservableCollection<news>();
//populate
Newsticker_Listbox.ItemsSource = newslist;
news is a really simple object, it just stores some strings, which can be read out by news.Title, news.Subtitle etc
I've used the example from http://www.geekchamp.com/articles/expand-and-collapse-expanderview-inside-data-bound-listbox-via-code as basic for my code, I've just simplified it for my cause (mabye too much?)
Help is very appreciated, thank you all in advance
EDIT
This code works so far, but why does the solution with templates not work?
<ListBox x:Name="Newsticker_Listbox">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="auto"/>
<RowDefinition Height="10"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
</Grid.ColumnDefinitions>
<toolkit:ExpanderView>
<toolkit:ExpanderView.Header>
<TextBlock Text="{Binding Titel}" />
</toolkit:ExpanderView.Header>
<toolkit:ExpanderView.Expander>
<TextBlock Text="{Binding Untertitel}" />
</toolkit:ExpanderView.Expander>
<toolkit:ExpanderView.Items>
<TextBlock Text="{Binding Text}" />
</toolkit:ExpanderView.Items>
</toolkit:ExpanderView>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>

Answer 1

Remove your Header={Binding} and Expander={Binding} XAML code. It is overriding your custom HeaderTemplate and ExpanderTemplate.
You bound the Header and the Expander to the context of the application, which it doesn't really understand, so the binding resolved itself to nothing, so your ExpanderView displays nothing.