Hmm...that's tough one.
You could try attaching something like the following as a .js file in the Resources section of the in5 dialog:
$(function(){
$('p').each(function(){
var p = $(this);
var ff = p.css('font-family');
if(ff.indexOf("Corporate A Pro")>-1) p.css('font-family','corporate-a, '+ff);
});
});
//---
That should save you from having to do a find and replace after each export.