WSDL-first approach: How to specify different names for wsdl:port and wsdl:binding?

You can try to implement IWsdlExportExtension and in ExportEndpoint modify wsdl:port/@name. Then implement IEndpointBehavior which will add your extension to an endpoint. To use your new behavior you have two choices:

• Add behavior from code. When service is hosted in IIS you have to create custom ServiceHost and ServiceHostFactory. In self hosting you can just iterate endpoints and add behavior.
• Add behavior from configuration. You must implement custom BehaviorExtensionElement, register this element and use it in endpointBehaviors related to your endpoint.

Here is simple example with extension element:

using System;
using System.Configuration;
using System.ServiceModel.Configuration;
using System.ServiceModel.Description;

namespace CustomWsdlExtension    
{
    public class PortNameWsdlBehavior : IWsdlExportExtension, IEndpointBehavior
    {
        public string Name { get; set; }

        public void ExportContract(WsdlExporter exporter, WsdlContractConversionContext context)
        {
        }

        public void ExportEndpoint(WsdlExporter exporter, WsdlEndpointConversionContext context)
        {
            if (!string.IsNullOrEmpty(Name))
            {
                context.WsdlPort.Name = Name;
            }
        }

        public void AddBindingParameters(ServiceEndpoint endpoint, System.ServiceModel.Channels.BindingParameterCollection bindingParameters)
        {
        }

        public void ApplyClientBehavior(ServiceEndpoint endpoint, System.ServiceModel.Dispatcher.ClientRuntime clientRuntime)
        {
        }

        public void ApplyDispatchBehavior(ServiceEndpoint endpoint, System.ServiceModel.Dispatcher.EndpointDispatcher endpointDispatcher)
        {
        }

        public void Validate(ServiceEndpoint endpoint)
        {
        }
    }

    public class PortNameWsdlBehaviorExtension : BehaviorExtensionElement
    {
        [ConfigurationProperty("name")]
        public string Name
        {
            get 
            { 
                object value = this["name"];
                return value != null ? value.ToString() : string.Empty; 
            }
            set { this["name"] = value; }
        }

        public override Type BehaviorType
        {
            get { return typeof(PortNameWsdlBehavior); }
        }

        protected override object CreateBehavior()
        {
            return new PortNameWsdlBehavior { Name = Name };
        }
    }
}

And configuration:

  <system.serviceModel>
    <extensions>
      <behaviorExtensions>
        <add name="portName" type="CustomWsdlExtension.PortNameWsdlBehaviorExtension, CustomWsdlExtension" />
      </behaviorExtensions>
    </extensions>
    <behaviors>
      <serviceBehaviors>
        <behavior>
          <serviceMetadata httpGetEnabled="true"/>
          <serviceDebug includeExceptionDetailInFaults="false"/>
        </behavior>
      </serviceBehaviors>
      <endpointBehaviors>
        <behavior name="customPortName">
          <portName name="myCustomName" />
        </behavior>
      </endpointBehaviors>
    </behaviors>
    <services>
      <service name="CustomWsdlExtension.Service">
        <endpoint address="" binding="basicHttpBinding" contract="CustomWsdlExtension.IService"
                  behaviorConfiguration="customPortName" />
        <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
      </service>
    </services>
    <serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
  </system.serviceModel>

My WSDL then looks like:

<wsdl:service name="Service">
    <wsdl:port name="myCustomName" binding="tns:BasicHttpBinding_IService">
        <soap:address location="http://localhost:2366/Service.svc" /> 
    </wsdl:port>
</wsdl:service>