Confused -> Silverlight 4 not allowing me to consume a WCF service using BasicHttpBinding?

OK I am totally confused and hopefully I am missing something here totally obvious. I am consuming a WCF service of mine (which is stable and working in ASP.NET) hosted in a Windows Service which uses a 'BasicHttpBinding' configuration. When I try to consume it from a Silverlight 4 application I get the following error in VS.NET:

*"Custom tool warning: Endpoint 'BasicHttpBinding_IMyService' at address 'https://mywcfservice:8000/WCFServices/MyService' is 开发者_Go百科not compatible with Silverlight 4. Skipping... MyService\Reference.svcmap"*

What!? I know and have gone through the hoops to jump through for making a netTCPBinding which has issues get past the error above in SL4, but why in the world is BasicHttpBinding having any issue with SL4? I thought since like day 1 of SL2 BasicHttpBinding was the defacto and easiest binding for Silverlight to consume. Here is my WCF server configuration:

  <service behaviorConfiguration="ServiceBehavior" name="MyService">
    <endpoint address="" binding="basicHttpBinding"
              bindingConfiguration="BasicHttpWindowsBinding"
              contract="IMyService"/>
    <endpoint address="mex"
              binding="mexHttpsBinding"
              contract="IMetadataExchange"/>
    <host>
      <baseAddresses>
        <add baseAddress="https://mywcfservice:8000/WCFServices/MyService"/>
      </baseAddresses>
    </host>
  </service>
</services>

<behaviors>
  <serviceBehaviors>
    <behavior name="ServiceBehavior">
      <serviceDebug includeExceptionDetailInFaults="false"/>
      <serviceMetadata httpsGetEnabled="true" httpGetEnabled="false"/>
    </behavior>
  </serviceBehaviors>
</behaviors>

<bindings>
  <basicHttpBinding>
    <binding name="BasicHttpWindowsBinding"
             maxReceivedMessageSize="214748"
             messageEncoding="Mtom"
             transferMode="Streamed">
      <security mode="Transport">
        <transport clientCredentialType="None"/>
      </security>
    </binding>

  </basicHttpBinding>     
</bindings>

What am I missing here? If anyone can help me or guide what might be incoorect please let me know. Thanks!

Edit: I think I might be on the trail - this service uses a 'Message Contract' as a parameter in a method and I wonder if this is causing any issues. However from this MSDN article: "Message contracts are supported in Silverlight 4" http://msdn.microsoft.com/en-us/library/cc896571(v=vs.95).aspx so I am still not 100% sure. I check 'Always generate message contracts' when consuming but it made no difference.

There are a few special attributes/values you use in your configuration file:

The BasicHttpWindowsBinding has transferMode and messageEncoding set to non default values.

According to WCF service for Sl3, which registered similar problems, you should do the following:

messageEncoding="Mtom"

Try: messageEncoding="Text" instead.

or transferMode="StreamedResponse"

Try: transferMode="Buffered" instead.

If you try these steps, you will probably get a running situation and can build in specifics from that point on, making sure it keeps working for the SL-WCF connection.