RESTEasy & JAXB: "BadRequestException: Could not find message body for type ..."

Issue

• I have a JAXB-annotated class as a resource.

• We're getting an error about not being able to find the appropriate message body reader

  org.jboss.resteasy.spi.BadRequestException: Could not find message body reader for type: class com.mstr.outbound.CallItem of content type: application/xml
  at org.jboss.resteasy.core.MessageBodyParameterInjector$1.createReaderNotFound(MessageBodyParameterInjector.java:73)
  at org.jboss.resteasy.core.messagebody.ReaderUtility.doRead(ReaderUtility.java:105)
  at org.jboss.resteasy.core.messagebody.ReaderUtility.doRead(ReaderUtility.java:93)
  at org.jboss.resteasy.core.MessageBodyParameterInjector.inject(MessageBodyParameterInjector
  

• We have a POST method wheren we want the body to be an xml representation of a single argument.

          @POST
       @Path("{subId}/{siteId}/immediate")
       @Produces("application/xml")
       @Consumes("application/xml")
       public ExampleResource resourceCall(CallItem callItem, @HeaderParam(value = "X-forwarded-for") String remoteIP,
                 @QueryParam("apiKey") String token, @PathParam("siteId") String siteId) throws RemoteException, ValidationException
       {