I have recently needed to address a very similar problem while working within a theme. The basis of the code was from this post and I had modified some of the code
The following is the first portion of the code I had modified.
add_action('init', 'limited_post_type');
function my_custom_limited_post_type()
{
$labels = array(
'name' => _x('Limited Post Type', 'post type general name'),
'singular_name' => _x('Film - DVD', 'post type singular name')
);
$args = array(
'labels' => $labels,
'public' => true,
'publicly_queryable' => true,
'show_ui' => true,
'query_var' => true,
'rewrite' => true,
'capability_type' => 'post',
'hierarchical' => false,
'menu_position' => null,
'supports' => array('title','editor','author','thumbnail','excerpt', 'page-attributes','custom-fields' ),
'show_in_nav_menus' => true
);
register_post_type('limited_post_type', $args);
}
The following is the second portion of the code I had modified.
foreach ( $scope as $scopeItem ) {
switch ( $scopeItem ) {
case "post": {
// Output on any post screen
if ( basename( $_SERVER['SCRIPT_FILENAME'] )=="post-new.php" || $post->post_type=="post" )
$output = true;
break;}
case "page": {
// Output on any page screen
if ( basename( $_SERVER['SCRIPT_FILENAME'] )=="page-new.php" || $post->post_type=="page" )
$output = true;
break;}
case "limited_post_type": {
// Output on limited post_type onlye
if ((basename( $_SERVER['SCRIPT_FILENAME'] )=="post-new.php" && $post->post_type=="limited_post_type" ) || (basename( $_SERVER['SCRIPT_FILENAME'] )=="post.php" && $post->post_type=="film_dvd" ))
$output = true;
break;
}
If you like please send me a message and I will gladly send you my functions.php file for your reference. This is definitely the way to make it happen though as I went through many nights of hair pulling as yourself.
