<xs:complexType name="SealStructure"> <xs:choice> <xs:element ref="ds:Signature" /> <xs:element ref="ts:Timestamp" /> <xs:element name="OtherSeal"> <xs:complexType> <xs:sequence> <xs:any namespace="##other" /> </xs:sequence> <xs:attribute name="Type" type="xs:token" use="required" /> </xs:complexType> </xs:element> </xs:choice> </xs:complexType>