PyGTK - Rollover Buttons

[Gepi Solo]

Hi, I'm a python newbie, coming from PHP & Perl. I'm developing client-server 
applications with a GUI. I'm trying to realize rollover buttons with images 
as background. I mean... I want to create a class which permit to create 
buttons with various shapes, (for instance something like this: O====O with 
a label and an image in the central part), that change their color/shapes 
when they have the focus on.
I split the image of the shape into 3 parts: left, center (which have to 
resize with the label in the button) and right.
I thought to Create an  EventBox (with the callback function connected to 
it).
Inside this EventBox I'd put a HBox with 3 elements: left image, another 
EventBox in the center, and the right image.
The EventBox in the center should have the central part of the shape-image 
as background and the Label of the button (and evenually an icon).

Am I right?? I don't know if it's the right way... I didn't find anything 
on this topic on Google. Anyway if it's the right way... I don't know how:
1. To put the central image as background in the inner EventBox(does the 
background image behave like in html tables where it repeats itself until 
it fill all the available space?)
2. To change all the images to realize the rollover effect
3. Trying to add an EventBox to the main window I noticed that it's grey 
and it covers the background image of the window. If I realize the button 
using the EventBox I'd like to see the window background image outside the 
shape of the button... (I don't know if it's clear... :) ) 

thanx in advance.
G.