[Opserty]

Here is a very rudimentary start I came up with. Still needs a lot of tweaking but I got it to work so it may help you:

PHP Code:

// I have used 7 as an example forumid, you will need to change it so it doesn't cause conflicts.
$vbulletin->forumcache[] = array(
        'forumid'   => 7,
        'styleid'   => 0,
        'title'     => 'Some Title',
        'title_clean' => 'Some Title',
        'description' => 'Some Description',
        'description_clean' => 'Some Description',
        'options'       => 73415,
        'displayorder' => 100,
        'daysprune' => -1,
        'newpostemail' => '',
        'newthreademail' => '',
        'parentid' => 3,
        'parentlist' => '7,3,-1',
        'password' => '', 
        'link' => '',
        'childlist' => '7, -1' ,
        'importforumid' => 0,
        'importcategoryid' => 1,
        'lastpostid' => 0 ,
        'showprivate' => 0 ,
        'defaultsortfield' => 'lastpost',
        'defaultsortorder' => 'desc',
        'podcast' => 0,
        'depth' => 0,
        'permissions' => array(
                4 => 655375,
                6 => 1048575,
                8 => 0,
                7 => 782847,
                2 => 782847,
                5 => 1048575,
                1 => 655375,
                3 => 655375
                                )
    );
$vbulletin->userinfo['forumpermissions'][7] = 1048575; 


EDIT: RE: Lastpostid. I'm not sure you can set your own thing in the last post column, since the lastpostid is cached for that forum and this is then most likely fetched from the database when the forumbit is processed. I'll have a look tomorrow to see if there is way to get around this.