for the post type

You have the solution, you need to enter a code in the wp_cpn_ouput_gen.php. Around line 33 is the next code:

$arg = array(
'cat' => $cat_id,
'numberposts' => $op['list_num'],
'orderby' => $wp_cpl_sort_array[$op['sort_using']],
'order' => ((true == $op['sort_order'])? 'ASC' : 'DESC'),
'post__not_in' => $op['exclude']
);

Just add your own line:

$arg = array(
            'post_type' =>  get_post_types(),
            'cat' => $cat_id,
            'numberposts' => $op['list_num'],
            'orderby' => $wp_cpl_sort_array[$op['sort_using']],
            'order' => ((true == $op['sort_order'])? 'ASC' : 'DESC'),
            'post__not_in' => $op['exclude']
        );

http://wordpress.org/plugins/wp-category-posts-list/