Active Trail for Forum

I had the problem, that I could not set the menu trail for the forum start page. Here is my solution:

in the Forum module line 864 there is a theme function: function theme_forum_display
if you copy that function in your template file and rename it as usual (function your_theme_name_forum_display), you can change the active menu item by changing the array('path' => 'forum', 'title' => $title) to the desired path in this part of the code:

// Breadcrumb navigation:
  $breadcrumb = array();
  if ($tid) {
    $breadcrumb[] = array('path' => 'forum', 'title' => $title);
  }

I don't think, this is a very clean solution. perhaps somebody knows how to put this in the Menu Trails module? I didn't find a proper hook...

Greetings,
lh