Note: Since Total 5.0 you can now enable this tab via the Post Types Unlimited plugin.
// Enable the "Media" post settings tab for custom post types
function my_add_meta_media_to_my_custom_type( $array ) {
$array['media']['post_type'][] = 'my_custom_type';
return $array;
}
add_filter( 'wpex_metabox_array', 'my_add_meta_media_to_my_custom_type', 40 );