I'm currently working on a WCF service that's exposed via a basicHttpBinding, with some exposition of the metadata via a WSDL url.
The metadata generator has been improved a bit since it is now split into multiple files, with references from the first wsdl to other URI's. There's not much to do to have that WSDL generated, and the generator take the liberty of using the machine's name to create reference URIs.
Most of the time, this is a good idea, but sometimes when your machine is behind a NAT gateway doing some port forwarding, your machine probably won't have the public FQDN used to access your gateway. You then end up with a root document referencing URI's with a host name that is not valid on the other side of the gateway.
The solution to change that behavior is quite simple : Just change the host name IIS is listening on. Use the MMC snap-in, and specify that your port 80 (or whatever port you're using) is listening on your external FQDN. WCF will then use that host name when generating URI's. Also don't forget that if you specify a host name, you might need to add an other entry to be able to access your website using "localhost".
This operation is also needed for servers farm when doing some load balancing.