intuit partner platform - Vendor Bill vs Vendor Credit / Ipp C# -

is there way using ipp (in c#) differentiate between bill , vendor credit? right when iterate through lines on bill payment (a check in case) show bills being paid vendor credits show not different bill (amounts positive, there no bill type etc).

intuit.ipp.data.qbo.billpaymentquery qbbillpaymentquery = new billpaymentquery();         qbbillpaymentquery.docnumber = "143766";         list<intuit.ipp.data.qbo.billpayment> qbobp = qbbillpaymentquery.executequery<intuit.ipp.data.qbo.billpayment>(context).tolist<intuit.ipp.data.qbo.billpayment>();          foreach (billpayment b in qbobp)         {             response.write("bill payment amount: " + b.header.totalamt + "<br>");              foreach (billpaymentline x in b.line)             {                 intuit.ipp.data.qbo.billquery qbbillquery = new billquery();                 qbbillquery.resultsperpage = 1;                 //qbbillquery.pagenumber = 1;                  qbbillquery.txnid = x.txnid;                 //qbbillquery.specifyoperatoroption(filterproperty.docnumber, filteroperatortype.equals);                    dataservices dataservices = new dataservices(context);                  bill b2 = new bill();                  b2.id = x.txnid;                  bill b3 = dataservices.findbyid(b2);                   response.write(b3.header.docnumber + " - " + x.amount + "<br>");                 }         } 

in qbo, vendorcredit not supported production use. available part of beta release. ref doc - https://developer.intuit.com/docs/0025_quickbooksapi/0050_data_services/v2/0400_quickbooks_online/0500_supported_entities_and_operations