1. A method for acquiring information for media independent handover (MIH) by a mobile station (MS), the method comprising: sending a privacy key management request (PKM-REQ) message to a base station (BS) to deliver an MIH query encapsulated in an MIH function (MIHF) frame, wherein the PKM-REQ message includes a PKM message code having a first value; receiving a privacy key management response (PKM-RSP) message from the BS as an acknowledgement to the MIH query, wherein the PKM-RSP message includes delivery method information for a response to the MIH query and a PKM message code having a second value; and receiving the response to the MIH query based on the delivery method information.