How to add fieldset to the partial node form

Hi,

I want to use the Drupal Core module 'book' in conjunction with the Commons WIki. Since I want that the user is able to quickly create and categorize a new Wiki entry, i need to display the fieldset of the book module (which appears in the vertical tab on node/add/wiki) also within the partial node form (PNF). Since you cannot manage this fieldset under admin/structure/types/manage/wiki/fields and then simply enable the "Display in the browsing widget mini-form", I need another approach. My idea was now to load the complete node/add/wiki form and save it into a variable $form_new, from which I extract the 'book' array and save it as $form['book'] of the partial node form, like this:

function commons_origins_form_commons_bw_partial_node_form__wiki_alter(&$form, &$form_state) {
	if (empty($form['#entity']) || $form['#entity']->type != 'wiki') {
		return;
	}

	module_load_include('inc', 'node', 'node.pages'); // loads the include file for node pages
        $form_new = node_add('wiki');

	if (isset($form_new['book'])){	
		$form['book']=$form_new['book'];
	}
#...do some more stuff
}

Now the fieldset 'book' is displayed in the PNF and displays all options I would have from node/add/wiki, but my settings are not stored after I press the save button of the PNF.

What can I do in order to properly implement the book fieldset into the PNF?
And: Is there a way to display to book/category within the teaser?