Now only mailwatcher's own icons are used by default. Instead it should use icons defined by the icon theme or at least have the possibility to choose icons from the icon theme (like launchers do). Now you only can choose pixmap files for them.
Now, the mailwatch has a possibility to choose icons from the icon theme using standard exo icon selection dialog. This makes the logical disjunction in this report to be true, so I am closing it as fixed.