The UltraESB from AdroitLogic fully supports REST! Thus you can use it to proxy GET, POST, PUT, DELETE, HEAD, OPTIONS and TRACE compliant with the HTTP spec RFC 2616!
For an example on the configuration, refer to this article "RESTful Proxy Services with the UltraESB" which describes how a JBoss RESTEasy service can be proxied via the UltraESB - and demonstrates the above REST methods, and the automatic 'Location' header re-writing etc, which allows the Proxy service to fully hide the real service.
The UltraESB also includes a very useful utility - the ToolBox! It allows one to play with all the above HTTP methods with an easy to use and intiutive graphical user interface. Read this article on how to use the ToolBox as an ESB and SOA test toolkit - "Getting started with the AdroitLogic ToolBox for the UltraESB"
As the UltraESB ships ready-to-run samples, you do not need anything other than the 25MB download available from http://adroitlogic.org/download.html And this includes ALL thats required to test this sample, including a sample RESTful service, and the HTTP/S client from the ToolBox