I resolve this issue.
DATA: LT_REQUEST_HEADER TYPE TABLE OF SBCHEADER WITH HEADER LINE,
LT_REQUEST_BODY TYPE TABLE OF SBCBODY WITH HEADER LINE,
LT_RESPONSE_HEADER TYPE TABLE OF SBCHEADER WITH HEADER LINE,
LT_RESPONSE_BODY TYPE TABLE OF SBCBODY WITH HEADER LINE.
APPEND 'Content-Type: text/xml; charset=UTF-8' TO LT_REQUEST_HEADER.
APPEND '<?xml version="1.0" encoding="euc-kr"?>' TO LT_REQUEST_BODY.
APPEND '<root> ' TO LT_REQUEST_BODY.
APPEND '<params> ' TO LT_REQUEST_BODY.
* (...blablabla...xml data string...)
* just call
CALL FUNCTION 'HTTP_POST'
EXPORTING
ABSOLUTE_URI = URI " url...
REQUEST_ENTITY_BODY_LENGTH = LV_LEN " blank variable.
RFC_DESTINATION = 'SAPHTTP'
* PROXY =
* PROXY_USER =
* PROXY_PASSWORD =
* USER =
* PASSWORD =
BLANKSTOCRLF = 'X'
IMPORTING
STATUS_CODE = STATUS_CODE
STATUS_TEXT = STATUS_TEXT
RESPONSE_ENTITY_BODY_LENGTH = LV_LEN
TABLES
REQUEST_ENTITY_BODY = LT_REQUEST_BODY
RESPONSE_ENTITY_BODY = LT_RESPONSE_BODY
RESPONSE_HEADERS = LT_RESPONSE_HEADER
REQUEST_HEADERS = LT_REQUEST_HEADER.
WRITE / 'THE HEADER DATA '.
LOOP AT LT_RESPONSE_HEADER.
WRITE:/ LT_RESPONSE_HEADER.
ENDLOOP.
WRITE:/ 'THE BODY DATA : ' .
LOOP AT LT_RESPONSE_BODY.
WRITE:/ LT_RESPONSE_BODY.
ENDLOOP.
When test program, use http monitoring tool(HTTP Analyzer...and so on...) and check http packit header.