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