show different value to actual value in combobox - is this possible

[Mike Martin <redtux1 googlemail com>]

Basically my question is :

In msaccess you can have a query linked to a combox with two or more
values, with the first being the data value and the second being for
presentation
You can have the "presentation" value appear in the combobox by hiding
the first column, but the first column is still the value that the
combobox is based on.

Is this possible in Gtk2