problem with menu

Hello,
I need help. I need some code or some plug-in, to solve the problem for me. The problem, which for me is very basic, it seems that no one had thought about it before, is that when I am in the menu and I have a page with a submenu, the mother page is not marked as active. I try to be more specific, I have a menu with 6 pages and when I am in each one, I have since to indicate which page I am on, a green line appears below the name of the page. So far so good. Now to the problem if I go to one of the two pages of the submenu, under the word of the menu the green line does not appear. How can I solve that? Can anybody help me?

The page I need help with: [log in to see the link]