I have a top drop down (sucker fish) nav menu having this structure

LINK-A
-submenu1a
--submenu1ab
-submenu2a

What I am trying to do is:
When "submenu1a" or ""submenu2a" or any other child item is active, I want "LINK-A"(the top item in the menu tree) active as well.

So in general terms; when the child link is active I want the top link in the tree higlighted as well as the child active link.

I had a look to the html code generated and unfortunately if i select a subitem from the dropdown menu the top level item in the menu does not have the "active" class

So
MENUitem (top of the tree) has CSS class "yuimenubaritemlabel yuimenubaritemlabel-hassubmenu" as al the other primary top link.
SUBMENUitem active has CSS class "yuimenubaritemlabel active yuimenubaritemlabel-hassubmenu"

Because the SUBMENUitem is hidden because is a dropdown subitem no active link is visible in the menu.

There is a usability reason behind my request: I'd like the user to know in which section of the site (LINK-X) he is in.

Have a look to my site www.carlesistrumenti.eu/ns (dev site)

Can anyone help?
THANKS