Why on earth do they want to pass request parameters in the header?
That sounds more probably like Suma's solution to the requirements rather than the actual requirement itself. Suma, why don't you post the requirement itself and somebody here would suggest a different approach to solve it.
I have heard occasional objections to passing parameters in the URL of a GET request. Usually, changing the request to POST (which then sends the parameters in the body of the request) is enough to convince doubters.