Hey. I'm utilizing a custom publish key in wordpress. I register this practice publish type such as this:

        register_post_type("lifestream", array(
            'label' => 'Lifestream',
            'public' => true,
            'hierarchical' => true,
            'menu_position' => 5,
            'supports' => array('title','editor','author','thumbnail','comments','custom-fields'),
            'taxonomies' => array('category','post_tag'),
            'query_var' => true,
            'publicly_queryable' => true,
            'exclude_from_search' => false,
            'caller_get_posts' => 1

        ));
        register_taxonomy_for_object_type('category', 'lifestream');
        register_taxonomy_for_object_type('post_tag', 'lifestream');

Within the theme (the loop template) I love to mix posts and my custom publish type, for your I'm using query_posts() with one of these parameters:

$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
$args = array(
    'post_type' => array('post', 'lifestream'),
    'paged' => $paged,
    'cat' => $wp_query->get('cat'),
    'tag' => $wp_query->get('tag'),
    'year' => $wp_query->get('year'),
    'monthnum' => $wp_query->get('monthnum'),
    'post_status' => 'publish',
    'showposts' => 3
);
query_posts($args); 


# the loop     
while ( have_posts() ) : the_post(); 
# markup
endwhile;


if($wp_query->max_num_pages > 1): 
# next_posts_link / previous_posts_link
endif;

wp_reset_query();   

This really is working to date. But, I acquired issues with the course and tags pages. Basically call the frontpage things are fine and that i can paginate with the pages obtaining the correct results.

And, basically call a paged URL, e.g. /category/mycat/page/2 a 404 is tossed. But there definitly ought to be posts. Whether you will find custom type posts or normale posts within the category. I guess that my parameters for query_posts() aren´t correct, but don´t know ...

It appears that $wordpress_query->max_num_pages has got the wrong value. Why? Will I register the taxonomies (I love to use groups and tags for my custom publish types) properly?

Have you got any Idea how to proceed? Thanks!

Make certain you add this:

'paged' => get_query_var('paged')

for your $args also it should accept the paging okay.

More here

Within the archive.php use the next:

query_posts( array(
  'post_type' => 'lifestream',
  'posts_per_page' => 6,
  'orderby' => 'menu_order',
  'orderby' => 'date',
  'order' => 'ASC',
  'paged' => '' . get_query_var('paged')
));

if ( have_posts() ) : while ( have_posts() ) : the_post();

endwhile; else:
endif;

For the following and former page links I personally use:

next_posts_link('Older Entries', $wp_query->max_num_pages);
previous_posts_link('Newer Entries', $wp_query->max_num_pages);