Here's request/response.
Request:
<?xml version="1.0" encoding="UTF-8"?>
<soapenv:Header>
<ns1:clientCustomerId>*******</ns1:clientCustomerId>
<ns1:developerToken>***********</ns1:developerToken>
<ns1:userAgent>*****</ns1:userAgent>
<ns1:validateOnly>false</ns1:validateOnly>
<ns1:partialFailure>false</ns1:partialFailure>
</ns1:RequestHeader>
</soapenv:Header>
<soapenv:Body>
<operations>
<operator>ADD</operator>
<operand>
<campaignId>93239114</campaignId>
<ns2:id>1022355</ns2:id>
<ns2:type>LOCATION</ns2:type>
</criterion>
</operand>
</operations>
</mutate>
</soapenv:Body>
</soapenv:Envelope>
Response:
<soap:Header>
<requestId>0004e968bbe662180a4253a6000030fa</requestId>
<serviceName>CampaignCriterionService</serviceName>
<methodName>mutate</methodName>
<operations>0</operations>
<responseTime>347</responseTime>
</ResponseHeader>
</soap:Header>
<soap:Body>
<soap:Fault>
<faultcode>soap:Server</faultcode>
<faultstring>[BetaError.BETA_FEATURE @ operations[0].operand.criterion; trigger:'1022355']</faultstring>
<detail>
<message>[BetaError.BETA_FEATURE @ operations[0].operand.criterion; trigger:'1022355']</message>
<ApplicationException.Type>ApiException</ApplicationException.Type>
<fieldPath>operations[0].operand.criterion</fieldPath>
<trigger>1022355</trigger>
<errorString>BetaError.BETA_FEATURE</errorString>
<ApiError.Type>BetaError</ApiError.Type>
<reason>BETA_FEATURE</reason>
</errors>
</ApiExceptionFault>
</detail>
</soap:Fault>
</soap:Body>
</soap:Envelope>
Kevin