I'm using W3 total cache for a while now with all my Wordpress installations. Just started to use CDN and I got some problems with leverage browser caching of my files (mostly images) that are served from my CDN. W3 total won't cache those files and I think because they are on a CDN.
I'm getting this message with Pingdom:
The following cacheable resources have a short freshness lifetime. Specify an expiration at least one week in the future for the following resources:
All files served from my CDN.
Is this a known issue or is it just me with this problem and doing something wrong?