BP-Corporate Navbar adding external links?

I would like to know the best way to add an external link or two to the BP-Corporate Navbar.

I built a free classifieds site in a subdirectory of my WPMU/BP install and I want to add the link to my navbar.

In the meantime i am just going to create a flashy banner to draw attention to my classifieds but ultimately I would like a link in my navigation since it is part of my overall community.

Thanks in advance.

If possible could you please post the correct code structure and then i can fill in the blanks.

I know how to do this in regular WP blogs which is very simple, but I know how tight the code is for Buddypress and I would like to have someone experienced with BP chime in.

Thanks