Lithium blog API. Can't list by post time

I noticed a problem with the order of blog posts that are retrieved from the Lithium api. I'm attempting to get a list of messages in order of "post time", but when I make the call, it seems to be returning in order of "edit time". Below is the call that I am making. Am I passing an incorrect param or if it's possible to achieve what I am trying?

http://tfhf.stage.lithium.com/restapi/vc/blogs/id/TeamUSA/messages/linear?restapi.format_detail=full_list_element&xslt=json.xsl&message_view.topic_sort_order=last_post_date

Thanks very much