To accomodating author feed into feedburner with this plugin, I added this code:
// Get author
$author = null;
if ($wp->query_vars['author_name'] != null) {
$author = $wp->query_vars['author_name'];
}
if ($author) {
$feed_url .= '_author_'.$author;
}
After this line:
// Get tag
$tag = null;
if ($wp->query_vars['tag'] != null) {
$tag = $wp->query_vars['tag'];
}
if ($options['feedburner_append_cats'] == 1 && $tag) {
$feed_url .= '_'.$tag;
}