When I use firebug, menu_down.gif replaces the root menu item hover background image no matter what I do.  (i.e. when I hover over a root menu item, the background image is menu_down.gif INSTEAD of menu_hover.gif repeated across x axis.)

Here's what I want to do:

1. Have a rootmenu item that replaces the background on hover (menu_hover.gif should be the background).

2. Have a submenu item that replaces the background on hover (submenu_hover.gif should be the background).

3. If a root menu item is present, I do NOT want the menu_down.gif arrow to be displayed.  I tried making the file transparent, but it completely replaces the background (i.e. menu_hover.gif no longer displays).

4. If a submenu item has its own subitems, menu_right.gif should be displayed. When hovering over, submenu_hover.gif is displayed as the background (in addition to the arrow) and the children links are displayed.