getting duplicate images with <mediaobject>

i'm testing generating PDF with xsltproc and FOP, and for
a simple <mediaobject>, i'm getting duplicate images being
inserted into the PDF file.

  here's my trivial mediaobject:

<section><title>Section 2</title>
 <para>
  This is a picture:
  <mediaobject>
   <imageobject>
    <imagedata fileref="xclock.jpg" align="center"/>
   </imageobject>
   <caption>
    <para>A regular xclock.</para>
   </caption>
  </mediaobject>
 </para>
</section>


  what gets generated is

------------------------------------------
This is a picture:


							[image of clock]

			A regular xclock.

							[another clock]

This is a picture:
------------------------------------------

  i'm just a bit baffled.  and if i remove the <caption>, i get only
one image, but i still get the duplicate line "This is a picture".

  suggestions?

rday