code: @Override
  	public HTTaxinvoiceXMLResponse getXML(String CorpNum, String NTSConfirmNum,
  			String UserID) throws PopbillException {
  		if ( NTSConfirmNum.length() != 24 )
  			throw new PopbillException(-99999999, "국세청승인번호가 올바르지 않았습니다.");
  		return httpget("/HomeTax/Taxinvoice/" +NTSConfirmNum+"?T=xml", CorpNum, UserID, HTTaxinvoiceXMLResponse.class);
  	}
docs: /*
  (non-Javadoc)
  @see com.popbill.api.HTTaxinvoiceService#GetXML(java.lang.String, java.lang.String, java.lang.String)