Updates: Status: WontFix Comment #3 on issue 36 by jmacau...@gmail.com: STP list http://code.google.com/p/ogf-nsi-project/issues/detail?id=36 I am closing this issue. Adding the order attribute is the only way to guarantee the original ordering of an array of like elements modelled in a <sequence>. For example, in the "StpListType" definition we have a single element definition that may have multiple instances. The XML/XSD specifications do not explicitly state that the instances of "stp" must be in original programatic order, just that they must exist. <xsd:complexType name="StpListType"> <xsd:sequence> <xsd:element name="stp" type="tns:OrderedServiceTerminationPointType" minOccurs="0" maxOccurs="unbounded" /> </xsd:sequence> </xsd:complexType> In JAX-WS this results in a List<OrderedServiceTerminationPointType> being created. The Java List<E> interface guarantees ordering based on positional insertion. However, other implementations may not use a structurally ordered type (i.e. Map), and therefore, original programatic order is not guaranteed. I believe the specification does indicate that different <elements> in a <sequence> must be ordered. For example, in PathType below directionality must occur before sourceSTP, sourceSTP before destSTP, etc. <xsd:complexType name="PathType"> <xsd:sequence> <xsd:element name="directionality" type="tns:DirectionalityType" default="Bidirectional"/> <xsd:element name="sourceSTP" type="tns:ServiceTerminationPointType" /> <xsd:element name="destSTP" type="tns:ServiceTerminationPointType" /> <xsd:element name="stpList" type="tns:StpListType" minOccurs="0" /> </xsd:sequence> </xsd:complexType> If anyone can find a specific standard-based definition the proves me wrong I will make the change.