I have never attempted what you are describing but I have forwarded my ports for NAT traversal for Bittorrents so I will list that procedure.
I am assuming you have assigned a static IP of 192.168.1.2 to your local computer and your internet is working fine from that computer.
I am assuming you have your local computer directly connected to the dsl modem.
I your modem setting page, go to "Advanced" and "NAT". "Virtual Server" should be selected by default. Click "Add"
Select "Customized Service"
Give it a suitable name.
Select desired protocol TCP or UDP or both
Define the ports to be forwarded in the "External Port" add specific port or a range of ports like 30200:30300
Add the same port or port range above in the "Internal Port"
In the "internal Server IP" add your local computer IP 192.168.1.2
Now your ports are forwarded to the local computer. if you have a torrent client you can check this quite easily. Use the forwarded port or port range to run services on the local PC.
I do not know the settings you need to do on the client side in order to run a service on your local machine as I have never done it myself but you ports are forwarded so any problem now must be on the client side or permissions required on local computer to allow a service to be run from a remote location.