QbXML for Adding an Invoice with Custom Fields

Example qbXML Request

 
<?xml version="1.0" encoding="utf-8"?>
      <?qbxml version="11.0"?>
      <QBXML>
        <QBXMLMsgsRq onError="continueOnError"><InvoiceAddRq>
  <InvoiceAdd defMacro="TxnID:Invoice19993557">
    <CustomerRef>
      <FullName>hardin,laquandus</FullName>
    </CustomerRef>
    <ClassRef>
      <FullName>Chicago</FullName>
    </ClassRef>
    <TxnDate>2014-06-16</TxnDate>
    <RefNumber>19671186</RefNumber>
    <BillAddress>
      <Addr1>LAQUANDUS  HARDIN</Addr1>
      <Addr2>17118 s locust dr</Addr2>
      <City>hazel crest</City>
      <State>IL</State>
      <PostalCode>60429</PostalCode>
    </BillAddress>
    <ShipAddress>
      <Addr1>LUCEO</Addr1>
      <Addr2>QUAN  HARDIN</Addr2>
      <Addr3>300 s Wacker</Addr3>
      <City>Chicago</City>
      <State>IL</State>
      <PostalCode>60606</PostalCode>
    </ShipAddress>
    <TermsRef>
      <FullName>Credit Card</FullName>
    </TermsRef>
    <SalesRepRef>
      <FullName>AS</FullName>
    </SalesRepRef>
    <ShipMethodRef>
      <FullName>UDS-G</FullName>
    </ShipMethodRef>
    <IsToBePrinted>true</IsToBePrinted>
    <InvoiceLineAdd>
      <ItemRef>
        <FullName>Harvest Flyer Small</FullName>
      </ItemRef>
      <Desc>Harvest Flyer Small - 16pc</Desc>
      <Quantity>1</Quantity>
      <Rate>26</Rate>
      <ClassRef>
        <FullName>Chicago</FullName>
      </ClassRef>
    </InvoiceLineAdd>
    <InvoiceLineAdd>
      <ItemRef>
        <FullName>ShippingCharge20</FullName>
      </ItemRef>
      <Desc>$20 shipping charge</Desc>
      <Quantity>1</Quantity>
      <Rate>5</Rate>
      <ClassRef>
        <FullName>Chicago</FullName>
      </ClassRef>
    </InvoiceLineAdd>
  </InvoiceAdd>
</InvoiceAddRq>
<DataExtAddRq requestID="86290">
  <DataExtAdd>
    <OwnerID>0</OwnerID>
    <DataExtName>Del. Phone #</DataExtName>
    <TxnDataExtType>Invoice</TxnDataExtType>
    <TxnID useMacro="TxnID:Invoice19993557"/>
    <DataExtValue>773-527-2199</DataExtValue>
  </DataExtAdd>
</DataExtAddRq>
</QBXMLMsgsRq>
      </QBXML>