What is correct syntax to connect via internet to Airport disk?

I know that I can access my USB drive that is connected to my Airport Extreme N over the internet. I know how to turn the option on. I told it to use the base station's password.

What I don't know is the exact syntax to access it remotely on a Windows machine. The drive is formatted Fat32, so I assume I use something like: afp://x.x.x.x When I try that it appears like it might be seeing it but it won't connect. I am assuming that it needs the password. What is the syntax to include the password in the address I use to connect to it?

Edit: When I try to connect it says that Windows cannot access the folder.

Thanks