Port Forwards can be configured on the TA's firewall in the same manner as outlined in this documentation:
Port Forwarding Quick Configuration Guide
[video] Configuring a Port Forward in AOS (NetVanta)
In short - Create an ACL matching the interesting traffic that needs to be port forwarded - Add a nat destination statement pointing to the local address as the new destination address matching traffic on the ACL you created on your WAN ACP - Make sure the ACP is applied to the WAN interface.
Hope this helps!
