Tooltip in GtkComboBox

[Gabriele Greco <gabriele greco darts it>]

Is possibile to assign different tooltips to the various elements in the
GtkListStore associated to a GtkComboBox?

I've added to the model a column with the tooltip but it seems GtkComboBox
do not have the API GtkTreeView has to do
this (gtk_tree_view_set_tooltip_column), nor anything similar...

I cannot find any hint about how to do this looking at the properties of the
objects involved (GtkComboBox, GtkTreeViewColumn, GtkCellRendererText and
GtkListStore)

I obviously googled for an answer before posting, without luck...

-- 
Bye,
 Gabry