RSS feed from several Custom Post Types filtered according to a Custom Taxonomy

Hi,

I developed a website with several custom post types.
I added a custom taxonomy ("Behaviors") to tell the site to select then display only the interesting posts.
I now want to create a RSS feed from those featured posts and Custom posts.

Here is what I did:
- accessed the Featured item page in the custom taxonomy and added /feed at the end of the URL (http://raulabad.staging.wpengine.com/post-behavior/featured/feed/)
- then added all custom post type slugs into the functions PHP code of the website as previously explained by Caridad.
Thus:

function myfeed_request($qv) {
	if (isset($qv['feed']) && !isset($qv['post_type']))
		$qv['post_type'] = array('post','articulos','infografias','videos','libros','enlaces','conferencias','certificaciones','formacion','presentaciones','testimonios','seleccion-semanal');
	return $qv;
}
add_filter('request', 'myfeed_request');

> It does not work, only the POSTS are displayed.
Please help.

Best,
Stephen