Firewall and vpn

Now i have a suse firewall2 installed Internet ----> Firewall2 ----> Lan In my lan i have a windows NT with vpn. I Know that i must open port 1723 and protocol 47 in my susefirewall2 to allow comunicate from internet to my server in NT Where can I open these ports in suse firewall2 scripts? and how redirect the traffic), Must i use iP-Tables on my rc-custom?. Help!!!