We are implementing Sharepoint to a design that has a top menu with
its flyouts arranged in a horizontal bar rather than the more common
vertical arrangement. We have found that the menu.orientation
property only changes the static menu to horizontal, but the dynamic
menu remains vertical. We have succeeded in making every
customization we need to a single menu item through CSS or the
DynamicItemTemplate tag, but have not found a way to change the
layout of the whole collection of menu items. We're stumped.

How do we go about changing the orientation of the flyouts to
horizontal?