DataSet generated by xsd.exe is not writing attributes on root element

Question

Child elements of my data are being written directly off the root element instead of off the element that is their parent in the schema.

My xsd:

<xs:schema xmlns="MyNameSpace" xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="MyNameSpace" elementFormDefault="qualified" attributeFormDefault="unqualified" version="1.0">
 <xs:import/>
 <xs:element name="DataFile">
  <xs:complexType>
   <xs:sequence>
    <xs:element name="LastUpdatedBy" type="xs:string"/>
    <xs:element name="DateTimeLastUpdate" type="xs:dateTime"/>
    <xs:element name="DataValues" maxOccurs="unbounded">
     <xs:complexType>
      <xs:all>
       <xs:element name="Num1" type="xs:int"/>
       <xs:element name="Num2" type="xs:int"/>
      </xs:all>
     </xs:complexType>
    </xs:element>
   </xs:sequence>
  </xs:complexType>
 </xs:element>
</xs:schema>

My input file:

<DataFile xmlns="MyNameSpace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="MyNameSpace MySchema.xsd">
 <LastUpdatedBy>Dan</LastUpdatedBy>
 <DateTimeLastUpdate>2009-12-07T16:40:30.0Z</DateTimeLastUpdate>
 <DataValues>
  <Num1>0</Num1>
  <Num2>0</Num2>
 </DataValues>
 <DataValues>
  <Num1>2</Num1>
  <Num2>0</Num2>
 </DataValues>
</DataFile>

What gets saved by MyDataSet.WriteXml(filename)

<DataFile xmlns="MyNameSpace">
 <LastUpdatedBy>Dan</LastUpdatedBy>
 <DateTimeLastUpdate>2009-12-07T16:40:30.0Z</DateTimeLastUpdate>
 <DataValues>
  <Num1>0</Num1>
  <Num2>0</Num2>
 </DataValues>
 <DataValues>
  <Num1>2</Num1>
  <Num2>0</Num2>
 </DataValues>
</DataFile>

The xmlns:xsi and xsi:schemaLocation attributes are not written. What do I need to do to preserve them?