Well, there is. But it's not really a trivial thing to do

A rough sketch of what's necessary:
a) create graphics in interface.fla, make them available to AS as classes (see properties of other elements, you'll get the idea)
b) change LibraryConstants.as and LibrarySWF.as, adding two constants and two cases for the two buttons
c) change gui/Navigation.as, around line 180 there's an array, add two entries for the buttons
d) set event type (best add in MegaZineEvent.as before)
e) add handling in MegaZine.as, function onNavigationMenu