Combine DataTrigger and Trigger in a MultiDataTrigger

I've seen from some examples that it is possible to combine this kind of trigger: ``` <Trigger Property="IsMouseOver" Value="True"> ``` With this kind of data trigger : ``` <DataTrigger Binding="{Binding IsHighlightable}" Value="True" /> ``` By using a MultiDataTrigger like this: ``` <MultiDataTrigger> <MultiDataTrigger.Conditions> <Condition Binding="{Binding RelativeSource={RelativeSource Self}, Path=IsMouseOver}" Value="True"/> <Condition Binding="{Binding IsHighlightable}" Value="True" /> </MultiDataTrigger.Conditions> <MultiDataTrigger.Setters> <Setter Property="BorderThickness" Value="1"/> <Setter Property="BorderBrush" Value="#BF6DBDD1"/> <Setter Property="Background" Value="{StaticResource SelectedItemBackgroundBrush}"/> </MultiDataTrigger.Setters> </MultiDataTrigger> ``` However, this does not work with attached properties. This trigger works: ``` <Trigger Property="UI:TreeViewHelper.IsMouseDirectlyOverItem" Value="True"> ``` But this does not work: ``` <MultiDataTrigger> <MultiDataTrigger.Conditions> <Condition Binding="{Binding RelativeSource={RelativeSource Self}, Path=UI:TreeViewHelper.IsMouseDirectlyOverItem}" Value="True"/> <Condition Binding="{Binding IsHighlightable}" Value="True" /> </MultiDataTrigger.Conditions> <MultiDataTrigger.Setters> <Setter Property="BorderThickness" Value="1"/> <Setter Property="BorderBrush" Value="#BF6DBDD1"/> <Setter Property="Background" Value="{StaticResource SelectedItemBackgroundBrush}"/> </MultiDataTrigger.Setters> </MultiDataTrigger> ``` Is there a way I could make the trigger work correctly inside the MultiDataTrigger? The IsMouseDirectlyOverItem property was taken from here http://blogs.msdn.com/b/mikehillberg/archive/2006/09/21/mytreeviewhelperismousedirectlyoveritem.aspx. Thanks