DOCBOOK: Nested Entities...

[James Oden <joden@eworld.wox.org>]

I am trying to generate a document that uses an external entity
that is itself used as document unto itself and has external entitities
it uses.  For instance:

	Document A -->  Document B --> Documents C-D

The reason I am doing this is that I trying to produce a larger 
customer document for our software, that includes a list of all of 
are apps error codes with descriptions.  Well that app actually the
error code entity as its config file (the goal being that the docs,
and the app all stay in sink because they are ultimately6 going to the
same source).  the problem is that error  entity also makes 
use of other external entities because some the text for the error codes
is exactly the same ofr some error codes.

My problem is, as far as I understand it an external entity must be
declared within the doctype, and having a doctype in both the customer
doc, and the error code doc, causes parsing of the error code doc to fail.

What can I do?

...james
P.S. I am very new to docbook and to xml/sgml so if this seems 
like a stupid question forgive me (if it seems like a newbie 
question, well I am newbie so that would be appropriate).  I did
try to search the archive though before I posted the question.