I need to use or stimulate a very simple session object inside my WCF app.
I simply need to store some values at the beginning of a call and I need access to these v
What you're describing (custom context that is retained for the life of a single request) is more like HttpContext.Items than an ASP.NET Session.
WCF does have a class called OperationContext that is similar to HttpContext. It doesn't have an Items property for custom context, but this blog post describes a technique you can use to achieve what you want.