Have you tried XML editor bundled in CF Bullder? If xml files are not associated with XML Editor of CF Builder, then right click a XML file in the Navigator view and select Open With->CF Builder XML Editor option.
I didn't know, explicitly, that this option existed.
I tried it and realized that this is what I must have seen before I started searching for another solution. I've been using XML Buddy in the past, and specified a DTD so I have tag insight specific to the XML configuration file.