code: @Override
  	public Date getCertificateExpireDate(String CorpNum)
  			throws PopbillException {
  		CertResponse response = httpget("/HomeTax/Cashbill/CertInfo", CorpNum, null,
  				CertResponse.class);
  		
  		try {
  			return new SimpleDateFormat("yyyyMMddHHmmss")
  					.parse(response.certificateExpiration);
  		} catch (ParseException e) {
  			throw new PopbillException(-99999999, "날자형식 포맷변환 실패["
  					+ response.certificateExpiration + "]", e);
  		}
  	}
docs: /*
  (non-Javadoc)
  @see com.popbill.api.HTCashbillService#getCertificateExpireDate(java.lang.String)