A DTD (say, a DocBook 4.5 DTD--the last normative version, 03 Oct 2006) only deals with document structure--not formatting a document. So, you would have to employ something else for formatting purposes, much like CSS formats XHTML code.
In the (XML) structured world using Adobe FrameMaker, you could run FrameMaker in its structured mode using a DTD file for the XML structure and an EDD file (that a template designer must create) for formatting purposes. The EDD file would typically be imported into an FrameMaker FM file template after it had been previously structured via a DTD file, the end result is a template file that an author could then utilize for authoring purposes, utilizing whatever formatting the EDD file was programmed to provide. Not an easy task--the creation of a formatting EDD.
OOo really never did much with its so-called DocBook XML. In fact, what little it had was for the DocBook version 4.1.2, which dates back to 18 Dec 2003.
BTW, I have created EDDs based upon DocBook 4.5 and DocBook 5.x, which were generated by FrameMaker from the DocBook DTDs. Generation of formatted DocBook-XML templates for documentation-authoring purposes is typically a job for an expert, so doing documentation with DocBook is definitely not for beginners. If anybody would care for some advice using FrameMaker's DocBook 4.5 or 5.x, I could give it.
There are other software applications that could be used. Sagehill has some documentation along those lines: http://www.sagehill.net/docbookxsl/
Gary.
Gary Schnabl
Southwest Detroit, two miles NORTH! of Canada--Windsor, that is...
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