how to extract column from xsd

i have a win app in c#. i have an xsd with symple type,restriction and union type. i would extract from my xsd all column that are or type "xs:date" or my custom type newdata

so in this xsd

  <xs:simpleType name="newdata">
    <xs:union memberTypes="xs:date">
     <xs:simpleType>
       <xs:restriction base="xs:string">
       <xs:pattern value="\d{2}[/]\d{2}[/]\d{4}"/>
       <xs:length value="10"/>
      </xs:restriction>
    </xs:simpleType>
   </xs:union>
   <xs:element name="DocumentElement">
   <xs:complexType>
   <xs:sequence>
     <xs:element maxOccurs="unbounded" name="UserSettings">
       <xs:complexType>
        <xs:sequence>
          <xs:element name="ID_UTENTE"  type="xs:decimal" />
          <xs:element name="DATA_INIZIO" type="newdata" />
          <xs:element name="NOME_UTENTE"  type="xs:string" />
          <xs:element name="DATA_FINE" type="xs:date" />

i would obtain colum name of DATA_INIZIO and DATA_FINE

How can i obtain them? thanks a lot