No one really knows why it doesn't work. It's not just my install, but it is apparently quite rare.
Well, then you are screwed. Without knowing what the actual problem is, then it's sorta difficult to fix it.
Future-dated posts with wp-cron never worked on my install.
Well, of course not. wp-cron isn't being allowed to work, so naturally, future dated posts are not going to work either, because it's wp-cron that actually *posts* them when it comes time to do so.
You can try this:
In wp-cron.php, you'll find this code:
if ( $_GET['check'] != wp_hash('187425') )
Comment that out by adding // in front of each line. This disables the check that prevents you from running it manually.
Next, you will manually run wp-cron.php by calling its address in a browser.
If this doesn't allow it to run, then you really are screwed and need to find a new webhost who doesn't have these sorts of issues. It will work on a standard box running standard configurations. Whatever they've done to break it makes them way, way non-standard.