Work around unsupported baseline-shift

Hi batik cracks,

as far I found out the CSS property baseline-shift is neither supported 
by IE 9.0 nor yet by Firefox. Unfortunately I'm now not only exposed 
these exotic (behaving) SVG renderers but mathematical formulas with 
lots of superscripts and subscripts on the SVG side as well.

I'm now considering to create a small converter which transforms 
"baseline-shift" CSS attributes into "dy" attributes. With some efforts 
I could solve this in XML, but since I am lazy and eager to use Batik 
I'd prefer some higher level API to use.

Could someone please light me the way how to do this with Batik?
Is my impression correct that I will need to use the GVT API?

Thank you!

Wulf