In the provided example the multiple dx and dy attributes an text or tspan elements aren't respected, only the first one is used. at http://www.carto.net/neumann/webkitsvgbugs/multiple_dx_dy_test_in_text_tspan.png you can see the correct rendering from Apache Batik. Thanks a lot for implementing this!
I think this is a dup of bug 6420.
*** This bug has been marked as a duplicate of 12698 ***