[solved]creating a tv value entry with an api call

I am testing revolution beta 4 to build a site containing up to 10000 user generated documents maybe more.

On submitting a formulary, the members can create a document that will be filled with $_POST values, like this :

$title=$_POST['title'];
$entry=$_POST['entry'];
$price=$_POST['price'];     // dont forget sanitizing

$doc = $modx->newObject('modDocument');
$data = array(
			'pagetitle'   	=> $title,
			'alias'   	=> insertDate().'-'.makeAlias($title),
			'template'   	=> 2,
			'introtext'   	=> substr($entry,0,255),
			'content'     	=> $entry,
			'context_key'  	=> 'web'
		);

Allright this works fine.

Now in the manager I have created some custom TVs linked to that document (price, ...) and I would like to set the $_POST[’price’] value into the database by adding an entry in the table modx_site_tmplvar_contentvalues.

I have no idea how to proceed and the doc doesn’t help.
Does someone know the api/xpdo calls that could do it ?

<?php
//assuming you have successfully saved the $doc
$tv = $modx->getObject('modTemplateVar', array('name' => 'price'));
$tv->setValue($doc->get('id'), $_POST['price']);
$tv->save();
?>

Thanks a bunch for the code !

documents are not separated in contexts but in containers by month, each month => a new container