<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:urn="urn:enterprise.soap.sforce.com" xmlns:urn1="urn:sobject.enterprise.soap.sforce.com">
    <soapenv:Header>
        <urn:SessionHeader>
            <urn:sessionId>00DF00000005uci!AQsAQOSw.aXapKRpHWPha0OfTSIawHpA.3qsQwYsgZ.FdQVw13X5CAdIoEcH0o4VgV3hegEMTKiKTnSn9dC8Ha8.lk0BjU4F</urn:sessionId>
        </urn:SessionHeader>
    </soapenv:Header>
    <soapenv:Body>
        <urn:upsert>
            <urn:externalIDFieldName>Customer_Number__c</urn:externalIDFieldName>
            <urn:sObjects xsi:type="urn1:Account" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
                <urn1:Customer_Number__c>55555</urn1:Customer_Number__c>
                <urn1:Name>John Smith Household</urn1:Name>
                <urn1:BillingStreet>2nd Main Street</urn1:BillingStreet>
            </urn:sObjects>
        </urn:upsert>
    </soapenv:Body>
</soapenv:Envelope>