Hi
I've seen the configuration and it look fine.
But i have one doubt to share with you.
I've faced problem before with HTTPs with one of my clients and after invistigating i noticed that the HTTPs session timed out before any reply.
So it was a timing issue, and i noticed that my client configured a Local DNS server that was 5 to 6 HOPs away from the LAN, and when i changed to alternative DNS which was 1 HOP, things startd to work fine.
Also, you can;t imagine that some HTTPs sites like the HOTMAIL, YAHOO MAIL login pages were perfect but not the GMAIL.
I suggest you see where the packet is being delayed and timed out.
Good Luck !!!