How to get the actual SOAP message from encrypted SOAP message passing through ESB action pipeline ?

Issue

• There is a scenario which includes a JBoss WS based WebService doing authentication using digital certificates for each SOAP message coming through each of it's invocation. There is an ESB application sitting between the WebService client and server code which proxies the incoming SOAP message for the server application.
  When the request comes to the ESB service, SOAP message is in encrypted format using digital certificate. In that case the action classes in the ESB service's action pipeline is unable to parse the SOAP message before it would get proxy by SOAPProxy action class. Perhaps the SOAP message flowing through the action pipeline's ESB message is encrypted too.
• How to get the actual SOAP message from encrypted form in an ESB action class?