New solution (as of October 2012)

Suffusion has added a new filter, making this process much easier (though if the action hooks used priorities, we could simply unhook the old action and add a new action rather than having to use this filter hack).

Use the appropriate code for your chosen theme location (Above or Below header).

Note in UberMenu 3, you can replace the uberMenu_easyIntegrate() functions below with the manual integration code generated in your Control Panel, for example ubermenu( 'main' , array( 'menu' => 34 ) );

Top Navigation (Above Header)

In your functions.php file, add:

function nav_uber(){
    uberMenu_easyIntegrate();
    return false;
}
add_filter( 'suffusion_can_display_top_navigation', 'nav_uber' );

Main Navigation (Below Header)

function nav_uber(){
    uberMenu_easyIntegrate();
    return false;
}
add_filter( 'suffusion_can_display_main_navigation', 'nav_uber' );

Then follow the guide for activating Easy Integration, and you should be all set!