HTTP caching is a good benefit. But you can get it just by using GET and shoving the body in the querystring. Headers: Use the SOAP ones, you're just tunneling

HTTP caching is a good benefit. But you can get it just by using GET and shoving the body in the querystring. Headers: Use the SOAP ones, you're just tunneling SOAP messages. Idempotentcy requires the app to implement it that way. HTTP doesn't really help there.