In the xsd we have:
+++
<xs:complexType name="common-load-metricType" abstract="true">
<xs:sequence>
<xs:element name="property" type="tns:propertyType" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
<xs:attribute name="weight" type="xs:int"/>
<xs:attribute name="capacity" type="xs:double"/>
</xs:complexType>
+++
So a getProperties() and a setProperties() should be added AbstractLoadMetric for example?