title: Missing TxnLineID for LineGroup in SalesReceiptAdd
body: <p>Working with examples I found I was able to add a SalesReceipt via QB WebConnector using QBXML.  Specifically I was adding a LineGroup (SalesReceiptLineGroupAdd) - and after adding that group I need to modify it.</p>
  
  <p>Well to modify it I need the TxnLineID of the LineGroup.  It did not appear in my results - although the add and response were successes.  Roughly here is the outline of the request:</p>
  
  <pre><code>&lt;?qbxml version="2.0"?&gt;
  &lt;QBXML&gt;
      &lt;QBXMLMsgsRq onError="stopOnError"&gt;
          &lt;SalesReceiptAddRq requestID="22"&gt;
              &lt;SalesReceiptAdd&gt;
                  ... customer, billing, etc...
                  &lt;SalesReceiptLineGroupAdd&gt;
                      &lt;ItemGroupRef&gt;
                          &lt;FullName&gt;2604-1&lt;/FullName&gt;
                      &lt;/ItemGroupRef&gt;
                      &lt;Quantity&gt;1&lt;/Quantity&gt;
                  &lt;/SalesReceiptLineGroupAdd&gt;
              &lt;/SalesReceiptAdd&gt;
          &lt;/SalesReceiptAddRq&gt;
      &lt;/QBXMLMsgsRq&gt;
  &lt;/QBXML&gt;
  </code></pre>
  
  <p>And in the response:</p>
  
  <pre><code>&lt;SalesReceiptLineGroupRet&gt;
      &lt;ItemGroupRef&gt;
          &lt;ListID&gt;800002A9-1389300902&lt;/ListID&gt;
          &lt;FullName&gt;2604-1&lt;/FullName&gt;
      &lt;/ItemGroupRef&gt;
      &lt;Desc&gt;test group 1&lt;/Desc&gt;
      &lt;Quantity&gt;1&lt;/Quantity&gt;
      ... etc ...
  </code></pre>
  
  <p>but I expected</p>
  
  <pre><code>&lt;SalesReceiptLineGroupRet&gt;
      &lt;TxnLineID&gt;619-1394725756&lt;/TxnLineID&gt;
      &lt;ItemGroupRef&gt;
          &lt;ListID&gt;800002A9-1389300902&lt;/ListID&gt;
          &lt;FullName&gt;2604-1&lt;/FullName&gt;
      &lt;/ItemGroupRef&gt;
      &lt;Desc&gt;test group 1&lt;/Desc&gt;
      &lt;Quantity&gt;1&lt;/Quantity&gt;
      ... etc ...
  </code></pre>
  
  <p>Based on the documentation.  What is wrong?</p>