Add custom post types to archive/sitemap

cpt_to_sitemap.php

<?php

// Add custom post types to archive/sitemap
add_filter( 'getarchives_where' , 'ucc_getarchives_where_filter' , 10 , 2 );
function ucc_getarchives_where_filter( $where , $r ) {

	$args = array( 'public' => true , '_builtin' => false );
	$output = 'names'; $operator = 'and';

	$post_types = get_post_types( $args , $output , $operator ); $post_types = array_merge( $post_types , array( 'post' ) ); $post_types = "'" . implode( "' , '" , $post_types ) . "'";

	return str_replace( "post_type = 'post'" , "post_type IN ( $post_types )" , $where );
	
}

?>