KeyBinding on a TreeViewItem

Question

I have a typical treeview and a viewmodel. The viewmodel has an observable collection of other viewmodels that serves as a data source for the tree.

public class TreeViewVM {
    public ObservableCollection<ItemVM> Items { get; private set; }
    public ItemVM SelectedItem { get; set; }
}

and the ItemVM :

public class ItemVM {
    public string Name { get; set; }
    public ImageSource Image { get; private set; }
    public ObservableCollection<ItemVM> Children { get; private set; }
    public ICommand Rename { get; private set; }
}

The view :

<TreeView Selecteditem="{Binding SelectedItem}" ItemsSource="{Binding Items}">
    <TreeView.ItemTemplate>
         <HierarchicalDataTemplate>
             <StackPanel Orientation="Horizontal">
                 <StackPanel.InputBindings>
                     <KeyBinding Key="F2" Command="{Binding Rename}"/>
                 </StackPanel.InputBindings>
                 <Image Source="{Binding Image}"/>
                 <TextBlock Text="{Binding Name}"/>
         </HierarchicalDataTemplate>
      </TreeView.ItemTemplate>
  </TreeView>

However my command will not be invoked no matter what I try as long as it is "inside" the HierarchicalDataTemplate.

If I move the KeyBinding in the TreeView.InputBindings (and the ICommand / RelayCommand from the ItemVM to the TreeViewVM) all is nice, the command gets invoked.

But I would like to have the command on the ItemVM (as it is where it makes sense). Any ideas?