conditional processing with mathml and equations as images

hi, I need to process my DocBook 5 xml to html for two different types of html: one uses mathml and the other type uses images for math content. 

Is the following pseudo-markup the appropriate structure? Here I use the informalequation element, but for a real document I would also include inlineequation with the same content structure.

informalequation

--mediaobject

----alt (contains escaped latex equation markup)

----imageobject condition=plain

------imagedata fileref=

----imageobject condition=fancy

------imagedata

--------mml:content

So I could process the xml with for condition=fancy to get the mathml rendered in the html and condition=plain to get img tags in the html.

Is this the right way to do this?

thanks,

--Tim