Listing child categories and posts

Hi

In my sidebar I would like to have a list of all the child categories and any posts under those child categories of a specific parent category. Here is an example:

ARTICLES

Brand
• Brand consistency

Brand something else

Printing

• Printing colour
• Paper

The parent category is: Site Articles

I have found two pieces of code that do part of what I want but I am not sure how to integrate the two.

This code displays all categories.

<?php
			//for each category, show posts
			$cat_args=array(
 			'orderby' => 'name',
  			'order' => 'ASC'
   			);
			$categories=get_categories($cat_args);
  			foreach($categories as $category) {
    		$args=array(
      		'orderby' => 'title',
      		'order' => 'ASC',
      		'showposts' => -1,
      		'category__in' => array($category->term_id),
      		'category__not_in' => array(4,5,6, 10),

      		'caller_get_posts'=>1
   			 );
    		$posts=get_posts($args);
     		if ($posts) {
        	echo '<li><a href="' . get_category_link( $category->term_id ) . '" title="' . sprintf( __( "View all posts in %s" ), $category->name ) . '" ' . '>' . $category->name. '</a> ';
        	foreach($posts as $post) {
          	setup_postdata($post); ?>

          	 <ul><li><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></li></ul></li>
          	<?php
        	} // foreach($posts
      		} // if ($posts
    		} // foreach($categories
			?>

This code displays the posts from the parent category:

<?php
//get all posts for children of category $cata
$cata = 16;
$taxonomy = 'category';
$cata_children = get_term_children( $cata, $taxonomy );

$args=array(
  'category__in' => $cata_children,
  'post_status' => 'publish',
  'posts_per_page' => -1,
  'caller_get_posts'=> 1
);
$my_query = null;
$my_query = new WP_Query($args);
if( $my_query->have_posts() ) {
  echo 'List of Posts belonging to Category A children';
  while ($my_query->have_posts()) : $my_query->the_post(); ?>
    <p><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></p>
    <?php
  endwhile;
}
wp_reset_query();  // Restore global post data stomped by the_post().
?>

I would really appreciate if if someone could help me out by showing me what code I need to do this?

Thank you so much.