First you need to wrap the mathML inside an element.
in your EDD you need to define a new element MathML which is MathMlEquation you also need to add InitailObjectFormat.-> All Context Rule ->MathMlEquation With Style -> Anchored frame Style.
Create an Anchor frame style with position as inline.
Also make sure that your dtd support your new MathMl Element.
Thanks. We do professional typography service wherein base-align needs to be 100% accurate and no negotiations applicable. Unfortunately, your suggestion would not work fit for our requirement. The purpose of FrameMaker for us is to expect the professional output in PDF.
Thank you so much for helping on this.