MathML Equations from MathFlow Render as Images Instead of XML

[ashrae-editor]

I have an unstructured Framemaker file in which I've created a number of MathML equations using MathFlow (as opposed to Framemaker's built-in equation builder). When I Publish this file as an ePub, however, Framemaker renders the equations as jpegs instead of XML.

Is my understanding of how this is supposed to work correct? That the MathFlow equations should appear as XML markup in the XHTML file within the ePUB file? If so, why doesn't it?

Thanks and regards.