IIS7 Rackspace CDN Leverage browser caching of static assets

I’ve been struggling a bit after being forced to an IIS platform. I would like to correct my ‘Leverage browser caching of static assets’ score. Currently I am using Rackspace as my CDN, but cannot seem to get things resolved. I am certain I have IIS setup properly but it doesn’t seem to change things.

Is there a setting on Rackspace to set these parameters? Or would it come from IIS? I believe I was using an .htaccess file in Apache. But am not sure.

I think you have a panel on Rackspace that could be usefull.
Did you see this post : http://cutfromthenorth.com/set-far-future-expires-headers-with-rackspace-cloud-files/ ? That could be a clue.