TreeView: Putting a widget on a CustomCellRenderer?

[Joao Victor <jvital gmail com>]

I'm taking a look at the TreeView tutorial avaliable on
developer.gnome.org, and there's a section on it where it talks about
custom cell renderers:

http://scentric.net/tutorial/sec-custom-cell-renderers.html

There's a function the tutorial's author wrote which is
'custom_cell_renderer_progress_render ', which is responsible for
doing the custom rendering.

My question is: can i modify that function to make it render a widget
inside the cell renderer? What i want is, for example, to put a Label,
or a text entry, *inside* a list cell.

If it is possible to that, can anybody give some tip on that, please?
Thanks,
J.V.