<schema xmlns="http://www.w3.org/2001/XMLSchema" xmlns:urn="urn:foo"
   targetNamespace="urn:foo">
   <simpleType name="myInt">
      <restriction base="int">
         <minInclusive value="1" />
      </restriction>
   </simpleType>
   <simpleType name="TimeOrDateTimeType">
      <union memberTypes="int urn:myInt" />
   </simpleType>
</schema>