Hi!
If Wordpress is configured to use HTTPS, the plugin will make CSS and HTML urls using HTTPS. But if only some part is in HTTPS, you will need to hack "autoptimize.php" around line 19, where it says
define('AUTOPTIMIZE_CACHE_URL',WP_CONTENT_URL.'/cache/autoptimize/');
You might want to replace it with something like this:
if($_SERVER['https'] == 1 || $_SERVER['https'] == 'on' || $_SERVER['SERVER_PORT'] == 443) {
define('AUTOPTIMIZE_CACHE_URL','https://mysiteurl.com/wp-content/cache/autoptimize/');
}else{
define('AUTOPTIMIZE_CACHE_URL',WP_CONTENT_URL.'/cache/autoptimize/');
}
It's based on this code -> http://wordpress.org/support/topic/264510?replies=1
Also, to do that modification you'll need Autoptimize 0.9 that I'll release later on today, or tomorrow. Check the version here: http://wordpress.org/extend/plugins/autoptimize/
Emilio