Originally Posted by KirbyDE

The AdminCP Navigation is now controlled through XML files.
To add custom entries, you must create a new file cpnav_yourhack.xml and place it in directory includes/xml.

This XML-File constist of 6 important tags:

• <navgroups>
  This indicates that this is a XML File containing navgroups.
  It has one parameter product that should be set to vBulletin
• <navgroup>
  This is the container for one Settings-Group, like Stales & Templates, vBulletin Options, etc.
  It has three parameters: phrase/text, permissions and hr.
  If you are using phrases, phrase must contain the variable name, if you are using hardcoded text then text must contain the label.
  Parameter permissions (optional) can be used to check an administrator permission, like canadminoptions.
  Parameter hr (optional) can be used to put a spacer below this navgroup.
• <navoption>
  This is one Menu-Entry.
• <phrase> or <text>
  This must contain the varname or hardcoded text for the menuetry.
• <link>
  Tag link must contain the URL.
  You can use {$vbulletin->config[Misc][modcpdir]} to point to the ModCP directory here, no matter how it is actually called

Example
Update for Beta 3
With Beta 3 a new parameter displayorder has been introduced. This parameter is valid for Tags navgroup and navoption.
This way it is possible to control in which order the Navgroups and Links will be displayed, and you can also add custom Links to existing Navgroups.
To do su, your navgroup must hav them same displayorder and Phrase Varname as the existing group:

Then Top-Link Forums & Moderators will be the first link in Navgroup Forums & Moderators (Displayorder: 60).

To find out the Displayorder for existing groups, take a look at cpnav_vbulletin.xml.