Okay, I've looked into this a little bit further, and it looks like the von Bloh paper is in A&A;: see http://www.aanda.org/index.php?option=article&access;=bibcode&bibcode;=2007A%2526A...476.1365VPDF

Tomorrow, I'll try to go through and update this reference, as it appears in more than a few articles.  I still maintain that it's too strong to claim that gl 581 c has been "shown" to lie outside the habitable zone, in light of the other reference, although a more thorough lit search is probably in order.