Terminal Server 2008 Web Access via Internet

I installed a 2008 Standard Server with TS or Terminal Services and all appears to work fine from within the LAN using XP machines with Srvpk3 and Vista machines w/Srvpk1. However, despite opening up ports 3389 and 443 on the firewall, I am still unable to access the TS from the internet? Has anyone come across this TS inaccessibilty issue from the internet and resolved it?