Hi there,
it took me a while to discover the reason why, after modifying SSLSubTrees[] in site.ini I was still getting pages in http mode.
Nor ezcache.php or clearcache.sh actually delete the file /var/siteaccess/cache/ssl_zones_cache.php when emptying the caches, hence resulting in non updated ssl zones.

Steps to reproduce

1. Activate SSLZones for a siteaccess
2. Define some SSLSubTrees
3. Verify it works (with template caching and compile enabled)
4. Modify the site.ini.append.php of the given siteaccess
5. Empty the caches either with ezcache.php or clearcache.sh
6. Verify that eZ Publish still returns the old ssl zones.

Deleting ssl_zones_cache.php by hand solves the problem.