[RESOLVED] WCF: Problems creating duplex contract

[chris128]

I'm trying to create a duplex contract in my WCF service, which from what I gather requires that you do the following:

Define an interface in your service, e.g IMyClientCallBack
Tell your main service to use that interface as its call back contract
implement the interface in your client

So I have the following on the server side:

''' <summary>
''' Main service
''' </summary>
<ServiceContract(CallbackContract:=GetType(IProtoChatCallBack), SessionMode:=SessionMode.Required)> _
Public Interface IProtoChatService
 
    <OperationContract()> _
    Function GetServerInfo() As ServerInfoDescription
 
    <OperationContract()> _
    Function GetUserList() As List(Of UserObject)
 
    <OperationContract()> _
    Function SignUserIn(ByVal iUName As String, ByVal iPassword As String) As SignInResult
 
    <OperationContract()> _
    Sub SignUserOut(ByVal iUName As String)
 
End Interface
 
''' <summary>
''' Call back contract that will be implemented on client side
''' </summary>
<ServiceContract()> _
Public Interface IProtoChatCallBack
 
    <OperationContract(IsOneWay:=True)> _
    Sub MessageReceived(ByVal SenderDisplayName As String, ByVal Message As String, ByVal TimeSent As DateTime)
 
    <OperationContract(IsOneWay:=True)> _
    Sub SignUserOut(ByVal Reason As String)
 
End Interface

However, now when I go to update the service reference on the client (so that I can define an implementation of the call back interface) I just get an error saying "Metadata contains a reference that could not be resolved".
If I take those 2 methods (MessageReceived and ForceUserSignOut) out of the interface then I can update the service reference on the client fine... but obviously there's not much use having a callback contract that doesnt do anything!

Anyone see where im going wrong?

Thanks
Chris