the pull request by craig has meanwhile been merged.
there is still a bit of issues:
the driver looks for the non-namespaced file. i.e. No mapping file found named '/home/david/liip/symfony-cmf/cmf-sandbox/vendor/symfony-cmf/routing-extra-bundle/Symfony/Cmf/Bundle/RoutingExtraBundle/Resources/config/doctrine/Route.phpcr.xml' for class 'Symfony\Cmf\Bundle\RoutingExtraBundle\Document\Route'.
but if i put that file there and have an error, he tells me Invalid mapping file 'Symfony.Cmf.Bundle.RoutingExtraBundle.Document.Route.phpcr.xml'
so the name determiner seems to be off a bit