image class or role in mediaobject

["Fabien Tillier" <f.tillier@cerep.fr>]

Hi List.
I want to add some tooling in the html output of my docbook for images,
and thus need to select only some of the ones I have displayed.
So, I have a class/role defined on the imagedata item
<mediaobject>
<imageobject class="imgopen2">
	<imagedata class="histogram" role="histogram" align="center"
fileref="{$path}" width="18cm" format="PNG"/>
</imageobject>
...
</mediaobject>
However, when generating the html version, the class is not propagate,
thus

   <div class="imgopen2">
        <table summary="manufactured viewport for HTML img" border="0"
cellpadding="0" cellspacing="0" width="638">
        <tbody><tr>
        	<td align="center">
			<img src="myImage.png" alt="title"
align="middle" width="638"></td>
         </tr>
         </tbody></table>         
   </div>
   
Note, however that the class define on the imageobject is kept.

Is there a way I can have the "histogram" class propagated at the image
level ?

Thanks in advance
Best regards,
Fabien