SDML or Vaxdocuments to docbook?

Hello!
I have a number of technical manuals written in Vaxdocuments, or
SDML (not SGML). It is
a tagged format, And I do have tex-versions, produced
from then sdml (which all have the extension .elem)
Does anyone know af a way to convert them to Docbook-xml?

Here's a small sample of the SDML

<COMMENT>
*******************************************************************************
<ENDCOMMENT>
                        <CHAPTER>(Environment \
                                  ch_Environment)
<P>
Some text from a system called <EMPHASIS>(VAX documents\BOLD) 

<P>
yet another paragraph from this ancient relik

  <LIST>(UNNUMBERED)
  <LE>
   a listitem 
  <LE>
   another listitem 
  <ENDLIST>

/Bj顤n Lundin