Check out Keith's blog on how to describe this REST scenario (posted by none other than Stefan) using WSDL 2.0. He does an existential proof of it showing not only how to describe it with WSDL 2.0 but how to implement it using the WSO2 Mashup Server.
Stefan, are you still not convinced that WSDL 2.0 can describe any REST scenario properly? If not please post another challenge.
I'd also like to challenge REST fans to show how the implementation Keith did is materially different from say a Java implementation that uses JAX-RS (Java API for RESTful Web Services - JSR 311) annotations (or any other Java programming model that you want).