Can't show child from a custom post type in archives

Hey guys
Ive triyng and researching a lot, but cant find a solution to this:
created (using types plugin) a post type named discografia.
then, another one, which i assigned as child from dicografia, named musica.

What i want is to display every musica child from a discografia.
Discografia shows itself like this:

<?php
$newsArgs = array( 'post_type' => 'discografia', 'posts_per_page' => 6);
    $newsLoop = new WP_Query( $newsArgs );
   while ( $newsLoop->have_posts() ) : $newsLoop->the_post();              

?>
<h1><a href="<?php the_permalink(); ?>" title="<?php the_title(); ?>"><?php the_title(); ?></a></h1>

(is a little more full of markup, but nothing unusual – just shoing thumbs and custom fields)

For testing purposes, i checked if every post shown has its id ok and save it in a variable

<?php $post_ied = get_the_ID(); 

echo $post_ied;
?>

it worked fine.

Now, i need to show musicas in every discografia listed above, i used snippet found on https://snipplr.com/view/62428/

i changed some variable names, so it dont fight with those i created before… lol

<?php $loope = new WP_Query( array( 'post_type' => 'musica', 'post_parent' => $post->ID, 'posts_per_page' => 30, 'order' => 'ASC' ) ); ?>

                                    <?php while ( $loope->have_posts() ) : $loope->the_post(); ?>

                                              <h2><a href="<?php the_permalink() ?>" rel="bookmark" title="<?php the_title_attribute(); ?>"><?php the_title(); ?></a></h2>

<?php endwhile; ?>

And it works. EXCEPT that it shows all musicas for every post from discografia, not only for its parents… got that?

i mean musica “MUSICA1” apears for both discografia “DISC1” and “DISC2”, but it is child of DISC1 only

I tried puting post->ID into a variable, but, even thou it work, it appears that ‘post_parent = something’ ist working =/

anyone?
Thnx a lot, i make lots of consults here , all the time, really, but this one i couldnt find the awnser…