Code:
<soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope">
<soap:Header>
<context xmlns="urn:zimbra">
<nosession/>
<authToken>auth token from AuthResponse goes here</authToken>
</context>
</soap:Header>
<soap:Body>
<SearchConvRequest xmlns="urn:zimbraMail" sortBy="dateDesc" offset="0" limit="25" cid="-560" fetch="1" read="1" html="1">
<query>in:inbox</query>
</SearchConvRequest>
</soap:Body>
</soap:Envelope> Your request replaces
SearchConvRequest and its children.