how to save an object with wcf rest?

Hello - I'm able to use the following code as an interface to allow my REST service to return a Customer object based on an ID parameter:

[OperationContract]
[WebInvoke(Method = "GET",
ResponseFormat = WebMessageFormat.Json,
BodyStyle = WebMessageBodyStyle.Wrapped,
UriTemplate = "Customers/{id}")]
Customer GetCustomer(string id);

Now I need to write an interface to allow my REST service to save a Customer object based on some Customer object XML.  Can you show me how I should put together that interface?