Feline,
Have you tried approaching this from RoboHelp instead? You can pull a FrameMaker document into a RoboHelp project by reference, meaning it is updated every time you open the project (possibly a refresh is required). The File > Publish from FM works through RH, so you would tap into the same publication track.
I know RH can be scripted, but I have not done anything in that area yet. Still, it could be worth looking at the documentation for RoboHelp Scripting to find out whether the proposed route would be feasible for you.
I am not someone to give up easily, as you may notice. :-)
Good luck
Jang