You will need to create an account in your DB for that person to begin with....
Code:
<IP> eqemu eqemu
<IP> <theirUN> <theirPW>
Then you would want to change your world address to be your external IP, so that they can access it, because as you probably know one cant access someone's internal IP from without.... Try that and let me know how that works out for you.. (I assume you know how to add an account into your DB)....