The plugin isn't contain within both fwcdn/S3.php and xml file.
The plugin also has got problem with img src= "" or img src= '' symbol.
We almost use the fastest way to modify the code to allow the code to support sub domain-- http://www.360.my/cms.
But not all files are loaded from CDN, especially some of the ico, css, js files, because it's called from other joomla module.
Thank you so much for the plugin. If anyone of you would like to know how to make it to support sub domain, please contact me, email@example.com
The plugin has been corrected since Joomla!2.5 update.
Please see changelogs for known issues and corrected bugs. As of your CR, regex expression has been modified to correct the '" pattern bug.
Thank you for your review.