Sorry, I completely missed that. I have checked in another fix that ensures the option works for both client and service code generation. You can grab the source from the change set below:
The name of the interface implemented by the service contract is now always used in the formatted SOAP action instead of the service contract class name.
e.g. Action="http://www.thinktecture.com/IRestaurantService/getRestaurants" instead of Action="http://www.thinktecture.com/RestaurantService/getRestaurants"
This change was required to make sure the option works for both client and service code generation, but actually follows the normal WCF behaviour for Action and ReplyAction more closely:
The default action value is a combination of the contract namespace (the default value is "http://tempuri.org/"), the contract name (interface name or the class name, if no explicit service interface is used), the
operation name, and an additional string ("Response") if the message is a correlated response.
Thanks for testing this and getting back to me.