In the logitech control centre, map the buttons you want to use for expose to the corresponding keystrokes (eg F9 etc). This requires a little logic - to be able to actually press F9 in the logitech control centre to tell it to bind the button to that key, you will have to temporarily remap the expose function bound to F9 to something else (in system preferences / keyboard and mouse / keyboard shortcuts).
So say you want 'all windows' to be the 'cruise up' button:
1) Go into keyboard preferences, set 'all windows' to be activated by F13 rather than F9, and F9 should now do nothing when pressed
2) Go back to the logitech control centre, map the cruise up button to F9
3) Go back to keyboard preferences, and set 'all windows' back to F9
4) ... Profit
