EWS. FindItem operation. How to map response data to the request?

Question

In my app I need to look for messages with certain custom properties. I'm using FindItem operation. This is the XML of my request:

<?xml version="1.0" encoding="UTF-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:mes="http://schemas.microsoft.com/exchange/services/2006/messages" xmlns:typ="http://schemas.microsoft.com/exchange/services/2006/types">
<soap:Header>
  <typ:RequestServerVersion Version="Exchange2010_SP2" />
</soap:Header>
<soap:Body>
  <mes:FindItem Traversal="Shallow">
     <mes:ItemShape>
        <typ:BaseShape>IdOnly</typ:BaseShape>
     </mes:ItemShape>
     <mes:Restriction>
        <typ:Or>
           <typ:IsEqualTo>
              <typ:ExtendedFieldURI PropertySetId="36603a56-9a21-4e9d-b4b7-6eb13876716a" PropertyName="OriginalId" PropertyType="String" />
              <typ:FieldURIOrConstant>
                 <typ:Constant Value="F33A7D78-5FCB-492E-AE98-D7E1CBB379C7" />
              </typ:FieldURIOrConstant>
           </typ:IsEqualTo>
           <typ:IsEqualTo>
              <typ:ExtendedFieldURI PropertySetId="36603a56-9a21-4e9d-b4b7-6eb13876716a" PropertyName="OriginalId" PropertyType="String" />
              <typ:FieldURIOrConstant>
                 <typ:Constant Value="hello-world-135" />
              </typ:FieldURIOrConstant>
           </typ:IsEqualTo>
           <typ:IsEqualTo>
              <typ:ExtendedFieldURI PropertySetId="36603a56-9a21-4e9d-b4b7-6eb13876716a" PropertyName="OriginalId" PropertyType="String" />
              <typ:FieldURIOrConstant>
                 <typ:Constant Value="9BA188D5-EC35-4E46-AA0B-1C902F6EE70E" />
              </typ:FieldURIOrConstant>
           </typ:IsEqualTo>
        </typ:Or>
     </mes:Restriction>
     <mes:ParentFolderIds>
        <typ:DistinguishedFolderId Id="sentitems" />
     </mes:ParentFolderIds>
  </mes:FindItem>
 </soap:Body>
</soap:Envelope>

So I'm looking for three messages as you can see. One of them (second one) doesn't exist. So in the response I expected to receive some indication that no data for this specific message was found. But this is what I get in the response:

<?xml version="1.0" encoding="UTF-8"?>
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
<s:Header>
  <h:ServerVersionInfo xmlns:h="http://schemas.microsoft.com/exchange/services/2006/types" xmlns="http://schemas.microsoft.com/exchange/services/2006/types" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" MajorVersion="15" MinorVersion="0" MajorBuildNumber="1365" MinorBuildNumber="1" Version="V2_23" />
</s:Header>
<s:Body xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <m:FindItemResponse xmlns:m="http://schemas.microsoft.com/exchange/services/2006/messages" xmlns:t="http://schemas.microsoft.com/exchange/services/2006/types">
     <m:ResponseMessages>
        <m:FindItemResponseMessage ResponseClass="Success">
           <m:ResponseCode>NoError</m:ResponseCode>
           <m:RootFolder TotalItemsInView="2" IncludesLastItemInRange="true">
              <t:Items>
                 <t:Message>
                    <t:ItemId Id="AAMkADE3MTJkZWNlLTZiYWYtNDY4Yi1hNmM3LWU2MzY2ZDZjYWNhMQBGAAAAAACoXti5FFu8TJNLLS5k9vC8BwAcJDq8WkSCQ77jdOtyazgnAAAAAAEJAAAcJDq8WkSCQ77jdOtyazgnAAEJ1zgKAAA=" ChangeKey="CQAAABYAAAAcJDq8WkSCQ77jdOtyazgnAAEJ7PHv" />
                 </t:Message>
                 <t:Message>
                    <t:ItemId Id="AAMkADE3MTJkZWNlLTZiYWYtNDY4Yi1hNmM3LWU2MzY2ZDZjYWNhMQBGAAAAAACoXti5FFu8TJNLLS5k9vC8BwAcJDq8WkSCQ77jdOtyazgnAAAAAAEJAAAcJDq8WkSCQ77jdOtyazgnAAEJ1zgJAAA=" ChangeKey="CQAAABYAAAAcJDq8WkSCQ77jdOtyazgnAAEJ7PHs" />
                 </t:Message>
              </t:Items>
           </m:RootFolder>
        </m:FindItemResponseMessage>
     </m:ResponseMessages>
  </m:FindItemResponse>
 </s:Body>
</s:Envelope>

Only two messages and no indication which ones in the request they belong to. So how am I supposed to map the two found messages to the data in request? Are the messages in the response actually 1 and 2? 2 and 3? or 1 and 3 (which is true in this case)? Do you see my confusion? Obviously I'm doing something wrong. There should be a way to map the data easily. How should I build the request the proper way?

UPDATE:

What I also tried was making a separate FindItem node for each message but unfortunately this didn't work either. The response contained data only for the first item

Answer 1

Your ItemShape element caninclude AdditionalProperties element where you can specify your custom properties, such as "OriginalId".