All navbar links are added in a template called 'navbar'. Look for code such as:
Code:
<if condition="$show['member']">
<td class="vbmenu_control"><a href="usercp.php$session[sessionurl_q]">$vbphrase[user_cp]</a></td>
</if>
And add the custom links under them. To remove default links, just search the default name or file name in the navbar template, and remove code that is similar to the above which needs removing.