Added correlation of messages with running workflow instances based on a server side behavior and a custom attribute. This way you can mark with an attribute on your operation or Data contract if your message needs correlation to an existing workflow. You can provide an additional mapping class that can do the lookup from a functional parameter to an Guid (by a database lookup or something else you use for housekeeping) and that mapping class is invoked to get the right workflow instance for the service call.
I also updated the samples and the step by step guide to show how it works. The project also contains unit tests to validate the correlation behavior.
Last but not least I added addition validation to properties to prevent runtime errors because of miss-configuration of the activities.
The release is fully compatible with the previous versions of the WCF activity and therefore I only bumped the file version number not the assembly version.
Please let me know if you find any issues, and I will try to resolve them a.s.a.p.