Configure Reporting Services proxy for Bing maps

Add the following XML element to the web.config of both folders:
...\MSSQL\MSRS11.MSSQLSERVER\Reporting Services\ReportManager\
...\MSSQL\MSRS11.MSSQLSERVER\Reporting Services\ReportServer\

Add at the end between the runtime close tag and configuration close tag:

</runtime>
<system.net>
     <settings>
          <ipv6 enabled="true" />
      </settings>
      <defaultProxy enabled="true" useDefaultCredentials="true">
           <proxy bypassonlocal="True" proxyaddress="http://:"/>
       </defaultProxy>
</system.net>
</configuration>

It might be needed to restart the Microsoft Reporting Services service.