How to change the font of GtkComboBox popup list

[Marco <mscholtn xs4all nl>]

Hi,

I'm trying to change the font of a GtkComboBox but i can only change the  
font of the the 'label' part (that what's visible when popup is inactive)
I cannot find a way to change the font of the popup entry's, i tried with  
gtk_container_forall() but that didn't work.
I have found a couple of simular questions with google, but no answers.  
(hope i will have more luck this time)
Has anyone successfully done this?, is it even possible?
I'm using gtk+ 2.4

Thanks for any help,

Marco Scholten