code: @Override
  	public Response registIssue(String CorpNum, Cashbill cashbill, String memo,
  			String UserID) throws PopbillException {
  		if (cashbill == null)
  			throw new PopbillException(-99999999, "현금영수증정보가 입력되지 않았습니다.");
  		if (memo != null)
  			cashbill.setMemo(memo);
  
  		String PostData = toJsonString(cashbill);
  
  		return httppost("/Cashbill", CorpNum, PostData,
  				UserID, "ISSUE", Response.class);
  	}
docs: /* (non-Javadoc)
  @see com.popbill.api.CashbillService#registIssue(java.lang.String, com.popbill.api.cashbill.Cashbill,
  java.lang.String, java.lang.String)