Ddocumentation for the custom rng schema?

Hi,

The custom RNG schema has following element definition:
<define name="dbx.parameterDescriptions">
    <element name="parameterDescriptions">
      <a:documentation>A top-level section of Parameter 
definitions.</a:documentation>
        :
        :

Any idea, how do I generate documentation for the custom rng schema?

TIA,
Anagha
PS: I am using DB5.