how to left-indent <programlisting>, <screen>??

["Robert P. J. Day" <rpjday@mindspring.com>]

  i wanted to automatically left indent some of the monospace
verbatim environments, and after checking some of the other
.xsl files in the fo/ stylesheets directory, as a first attempt,
i tried adding the customization:

<xsl:attribute-set name="monospace.verbatim.properties">
 <xsl:attribute name="start-indent">0.25in</xsl:attribute>
</xsl:attribute-set>

  (NOTE that this is not the ideal approach in case i wanted
to have different amounts of indentation for the different
monospace verbatim environments, but i figured it was a 
good first attempt.)

  while the above *did* in fact generate the proper left indent
for my sample <screen> and <programlisting>, it *totally* 
screwed the contents of those elements.

  suddenly, their contents were justified (that is, both left
and right, massive amounts of inserted white space) while, 
for the most part, the font reverted from monospace to regular
for both elements.

  this is not what i expected.  is there any reason (or docs)
to explain why simply adding that "start-indent" attribute would
cause this kind of change in processing?  (can anyone reproduce
this, just so i know i'm not hallucinating?)

  and, on a related topic, is there a better way to add that
kind of customization so that i can do it on a per-element
basis?  would it make sense to wrap the element in a 
fo:block with a "start-indent" attribute instead?

just another day of docbook enlightenment,
rday