I would like to create an XSD that will verify the xml below has one
<config> element with the name  attribute equal to 'DBC'  all other
<config> elements are optional and their values don't matter.  I
cannot restrict other <config> elements from being there.  Is this
possible with XSD?  If so could someone help me with an example?

<-- This should be VALID be cause it has one and only one config
element with name 'DBC' --/>
<project>
   <config name='DBC' output='myprogram.exe'>
       <file>myfile.dbr</file>
  </config>
  <config name='Make' output='myprog.exe'>
      <file>myfile2.dbr</file>
  </config>
</project>

<-- This should be VALID be cause it has one and only one config
element with name 'DBC' --/>
<project>
   <config name='DBC' output='myprogram.exe'>
       <file>myfile.dbr</file>
  </config>
</project>

<-- This should be INVALID be cause it does not have a config element
with name 'DBC' --/>
<project>
   <config name='comp.bat' output='myprogram.exe'>
       <file>myfile.dbr</file>
  </config>
  <config name='Make' output='myprog.exe'>
      <file>myfile2.dbr</file>
  </config>
</project>