I'm looking at implementing some WCF Services as part of an API for 3rd parties to access data within a product I work on. There are currently a set of services exposed as "classic" .net Web Services and I need to emulate the behaviour of these, at least in part.

The existing services all have an AcquireAuthenticationToken method that takes a set of parameters (username, password, etc) and return a session token (represented as a GUID), which is then passed in on calls to any other method (There's also a ReleaseAuthenticationToken method, no guesses needed as to what that does!).

What I want to do is implement multiple WCF services, such as:

• ProductData
• UserData

and have both of these services share a common implementation of Acquire/Release. From the base project that is created by VS2k8, it would appear I will start with, per service:

public class ServiceName : IServiceName
{
}
public interface IServiceName
{
}

Therefore my questions would be:

1. Will WCF tolerate me adding a base class to this, public class ServiceName : ServiceBase, IServiceName, or does the fact that there's an interface involved mean that won't work?
2. If "No it won't work" to Question 1, could I change IServiceName so it extends another interface, IServiceBase, thus forcing the presence of Acquire/Release methods, but then having to supply the implementation in each service.
3. Are 1 and 2 both really bad ideas and there's actually a much better solution that, knowing next to nothing about WCF, I just haven't thought of?