setParameter[s]() examples on DQL page uses ":" even though that is not supported

http://www.doctrine-project.org/docs/orm/2.0/en/reference/dql-doctrine-query-language.html

Among others:
$query = $em->createQuery('SELECT u from ForumUser u WHERE (u.username = :name OR u.username = :name2) AND u.id = :id');
$query->setParameters(array(
':name' => 'Bob',
':name2' => 'Alice',
':id' => 321,
));

Despite this does not work and doc says "When referencing the parameters in Query#setParameter($param, $value) both named and positional parameters are used without their prefixies." on same page.
(side note: prefixies => prefixes)

Fresh on doctrine 2.0 you typically copy past examples to try out stuff, and when exception then says that ":id" is not a valid param on this query you end up not knowing what went wrong.