Each theme registers different theme locations in which to place the menu. If your new theme still supports WordPress 3 Custom Menus, all you’ll need to do is go back to Appearance > Menus, set your menu to the new Theme Location and activate that location with UberMenu (setup instructions steps 6-7). If your new theme does not support WP3 Menus, you’ll need to use easy integration.
Heads up!
This archived doc is for an old version of UberMenu.
For the current documentation, please visit the UberMenu 3 Knowledgebase