Can XML be documented using Doxygen, Sandcastle, or other documentation generators?

I am currently using Sandcastle, Doxygen, and JavaDoc to generate documentation for code I have written. Is it possible to document XML schemas using these packages? If not, are there any (preferably free!) packages which can do this? I could write the documentation myself as an extra conceptual topic within Doxygen or Sandcastle, but I would rather a tool did it for me!

An example would be (although I am no expert at XML Schema!):

开发者_StackOverflow/// <summary>Top Node</summary>
<xs:element name="TopNode">
    /// <summary>Child Node</summary>
    <xs:element name="ChildNode" type="xs:string"/>
</xs:element>

The only tool that I know of that can document XML schemas is DocFlex/XML XSDDoc. Quite frankly, I don't have much experience using it but for what little use I did have of it, it did a pretty good job.

I've just started using XML Schema Documenter which integrates with Sandcastle Help File Builder and its a great combination for my needs which are a .NET plugin framework that has XML based configuration.