If you are using WSSF along with EntLib, then you might what to check this out in the WSSF Contrib Project site.
As you will find on the documentation provided, along with some walkthroughs and samples, here are the brief description:
The goal of these extensions is to simplify the task of integrating PIAB and WCF by providing the following features:
- Design time support for applying policies to services.
- Generating a host config file pointing to an external EntLib configuration file.
- Implementing a WCF behavior that abstracts you from wrapping or creating objects using the PIAB factory (read: MSDN article).
You can also download the latest version from here.