alt text for inlineequation

Hi,
I'm using DocBook5 and the docbook-xsl-ns-snapshot from June 9; I want to get the alt text from

<inlineequation>
  <inlinemediaobject remap="math">
    <alt>$F$</alt>
      <imageobject>
        <imagedata fileref="images/w.png"
                   contentwidth="10px"
                   contentdepth="10px" role="math"/>
    </imageobject>
    <textobject role="tex">
      <phrase>$F$</phrase>
    </textobject>
  </inlinemediaobject>
</inlineequation>

I'd like to get the html:
<img src="images/w.png" width="10" height="10" alt="$F$" >

but I'm missing the alt text.

The DocBook XSL book mentions that this does work for a mediaobject. Shouldn't it also work for an inlinemedia object? I tried it as the first child of inlineequation which is legal but it made no difference to the html alt text.

thanks for any pointers,
--Tim Arnold