Nicolo,
I assume you would actually need to ask for it . You could send your peer a message, having him respond to it with an IP Address.
Although, I'm not sure why you even need it? I assume you used a relay exactly because you couldn't reach him directly.
However, I assume that you actually don't even need it. You can simply set 127.0.0.1 or 0.0.0.0 as a RemoteAddress parameter in the Add method call (when adding a tunnel). Something like:
[code]
wodVPN1.Channels.Add TCPLocalListen, 127.0.0.1 , 80, 127.0.0.1 , 80
[/code]
The above will create a tunnel from which it will forward any connection coming on your local port 80 to your peer's port 80.
Hope this helps.
Regards,
Damba