[Inkscape-devel] Extensions question - changing user's selection

Inkscape signals to an extension that the user has selected one or more items by passing an --id parameter to the new process running the extension. The inkex.py file looks for these and groups them under inkex.selected for easy retrieval.

I want to change the user's selection in my extension (they pick one path, I want to add to that selection).

I can see (thanks to perspective.py) how to tell a new inkscape process which items are selected and that it should work on. BUT I can't see how to signal back to the original inkscape my new set of selected paths. (I was hoping for a inkex.setselected() to match the inkex.getselected() )

How is it done, is there an example ?