bonobo, gtk widgets, DOM

Hi,

we're about to bonobo-ize gtkmathview, a GTK widget for rendering and
editing MathML markup. It occurs that most of gtkmathview's API (and all
of its own signals) involve DOM nodes. For instance, if I want to select
a given MathML element I send gtkmathview a reference to the DOM node I
want to select. From there gtkmathview recovers a pointer to the
internal data structure used to render the node, and updates the view.

Now, this works nicely as long as the widget and the container
application share the DOM tree in the same address space. As with bonobo
this not guaranteed anymore, how should I approach the problem? I can
see three ways:
a) bonobo-ize our DOM implementation (long and heavy)
b) make sure somehow that the widget and the container application share
the same address space (has this anything to do with in-proc
components?)
c) mapping DOM nodes to IDs and using such IDs for communication

Given that I'm just at the beginning with bonobo and its related
technologies, I might have overlooked something obvious or anyway
simpler. Can anyone on the list comment on these points?

Thank you,
-- luca