I were able to manage this by a tweak.. not sure this can be classified as a actual/perfect solution.
Observation: CXF produces in POJO mode when encountering a oneway operation assumes the endpoint to be "InOnly" hence from a route perspective it is a fire and forget - which indicates that even in an event of exception from the Target WebService provider the route will not wait to receive it.
Tweak-Solution: I have changed the target service's correspondiong wsdl file in such a way that the particular operation is got a response of type String (an arbitrary response) - this made the generated(out of wsdl to java pluggin) client code not having 'one-way' annotation which turn makes the CXF endpoint not to be "InOnly" exchange pattern.
Now, we are able to see response in case of a fault - eg: http 500/401 etc.
It would be helpful in case experts over here could comment so to identify a better approach.