> I have not been able to find a solution to this problem.
> Instructions in
> the EAD Cookbook for the use of SX (part of the SP package)
> suggest manually
> adding the DOCTYPE declaration post conversion.   SP clearly
> parses the SGML
> source document but seems to output only well-formed XML.  A curious
> approach.

As a *very* general rule, the SGML dtd is of little use
in an XML world, so it kinda, makes sense.

Have a look at http://www.jclark.com/sp/sx.htm

He wrote it, and has a page dedicated to it.
And no, there is no such option.

Regards DaveP