The camel-cxfrs doc writes that HTTP_PATH is required for camel-cxfrs producer when it's used with httpClientAPI option.
The CXF JAXRS front end also provides a http centric client API. You can also invoke this API from camel-cxfrs producer. You need to specify the HTTP_PATH and the HTTP_METHOD and let the producer use the http centric client API by using the URI option httpClientAPI or by setting the message header CxfConstants.CAMEL_CXF_RS_USING_HTTP_API.
However, when Camel transport is used between CXFRS producer and consumer, the invocation succeeds only if it sets HTTP_URI, not HTTP_PATH, to the header.
Otherwise it fails with 404 error.