_sip_copy_header
ret = _sip_copy_header(_new_msg, header, NULL, B_TRUE);
ret = _sip_copy_header(_new_msg, header, extra_param, B_TRUE);
ret = _sip_copy_header(_new_msg, header, NULL, B_FALSE);
extern int _sip_copy_header(_sip_msg_t *, _sip_header_t *, char *,
ret = _sip_copy_header(_sip_msg, _sip_header, param, B_TRUE);