You suggestion is correct:
Code:
<dm:ClassOfInanimatePhysicalObject rdf:ID="C030cd253-e528-11e1-aff1-0800200c9a66">
<rdf:type rdf:resource="&owl;Class"/>
<rdfs:subClassOf rdf:resource="&rdl;RDS270269"/> <!-- ON OFF CONTROL -->
<rdfs:subClassOf rdf:resource="&rdl;RDS882179"/> <!-- PNEUMATIC CONTROLLER -->
<rdfs:label>CO_PIC-101</rdfs:label>
<meta:valEffectiveDate rdf:datatype="&xsd;dateTime">2013-07-20T13:02:00Z</meta:valEffectiveDate>
</dm:ClassOfInanimatePhysicalObject>