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Use this patch file and it should work for you.

<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore>
    <settings>    
      <setting name="ItemNameValidation">
        <patch:attribute name="value">^.*$</patch:attribute>
      </setting>
   </settings>
  </sitecore>
</configuration>

According to this regex .* matches any character. And you will be able to create items. Here is the screenshot.

Hope this helps.