plone navigation current folder/ node

I wonder if I am missing here – While the plone navtree is set up to help me apply a style to the currently selected item, I can’t think of a way to apply a style to the parent folder of that item. If the current location is something like:-

root -> sub-folder 1 -> item 3

“item 3″ will have a class of :”navTreeCurrentItem” applied to it, but I would also like “sub-folder 1” to have a class, something like “navTreeCurrentNode” so that I could apply a style to that too.

I can’t think of a straightforward way (well, any way in fact, I get so lost trying to find the relevant bit of code in plone 2.5) to do this, please let me know!