<xs:schema targetNamespace=“www.tempuri.org/ImportedSchema” elementFormDefault=“qualified” xmlns:tns=“www.tempuri.org/ImportedSchema” xmlns:xs=“www.w3.org/2001/XMLSchema”>

<xs:complexType name="AnotherType">
  <xs:sequence>
    <xs:element name="B">
      <xs:complexType>
        <xs:sequence>
          <xs:element name="MyB" type="xs:string" />
        </xs:sequence>
        <xs:attribute name="BID" type="xs:int"/>
      </xs:complexType>
    </xs:element>
  </xs:sequence>
</xs:complexType>
<xs:element name="AnotherElement" type="tns:AnotherType">
  <xs:key name="AnotherKey">
   <xs:selector xpath="tns:B"/>
   <xs:field xpath="@BID"/>
  </xs:key>
</xs:element>

</xs:schema>