Because I wasn't so clear on my example.
This is what I exactly need:
<div class="post-container">
<div class="post-container-top"></div>
<div id="post-<?php the_ID() ?>" class="<?php thematic_post_class() ?>">
<?php thematic_postheader(); ?>
<div class="entry-content">
<?php the_content(''.__('Read More <span class="meta-nav">»</span>', 'thematic').''); ?>
<?php wp_link_pages('before=<div class="page-link">' .__('Pages:', 'thematic') . '&after=</div>') ?>
</div>
<?php thematic_postfooter(); ?>
</div><!-- .post -->
<div class="post-container-bottom"></div>
</div>
But is not just that. I had to change so many things, like, for instance, the navigations DIVs position:
<div id="container">
<div id="content">
<div id="nav-above" class="navigation">
<?php if(function_exists('wp_pagenavi')) { ?>
<?php wp_pagenavi(); ?>
<?php } else { ?>
<div class="nav-previous"><?php next_posts_link(__('<span class="meta-nav">«</span> Older posts', 'thematic')) ?></div>
<div class="nav-next"><?php previous_posts_link(__('Newer posts <span class="meta-nav">»</span>', 'thematic')) ?></div>
<?php } ?>
</div>
And:
<?php thematic_sidebar() ?>
<div id="nav-below" class="navigation">
<?php if(function_exists('wp_pagenavi')) { ?>
<?php wp_pagenavi(); ?>
<?php } else { ?>
<div class="nav-previous"><?php next_posts_link(__('<span class="meta-nav">«</span> Older posts', 'thematic')) ?></div>
<div class="nav-next"><?php previous_posts_link(__('Newer posts <span class="meta-nav">»</span>', 'thematic')) ?></div>
<?php } ?>
</div>
<?php get_footer() ?>
These things I don't think can be solved filtering functions, so as I had to change a lot, I've solved also my first issue.