The HighlightPath feature wasn't working for me, so this is what I came up with.
Using Firebug I noticed that the active menu item, based on the URL, has the "k-state-highlight" class. To cause it to appear selected, I use the jQuery statement below to add the "k-state-selected" class.
I placed this in a document ready function just after the menu.
To do a similar thing for sub-pages that don't get the "k-state-highlight" class, I use a selector to find the menu item by its href value.
I hope this helps somebody else.