Conditionally replace primary navigation menu for front page. (question here: http://www.studiopress.com/forums/topic/genesis-menus/)

functions.php

<?php

// Add this to your functions file, but do not include the lines above this!

add_action( 'template_redirect', 'remove_nav_exclude_blog_page' );
/**
* @author Brad Dalton - WP Sites
* @learn more http://wpsites.net/web-design/conditionally-remove-your-primary-secondary-nav-menu/
*/
function remove_nav_exclude_blog_page() {
	if ( is_front_page() ) {
		remove_action( 'genesis_before_header', 'genesis_do_nav' );
	}
}

add_action( 'genesis_before_header', 'custom_front_page_menu' );
function custom_front_page_menu() {
	if ( is_front_page() ) {

		$class = 'menu genesis-nav-menu menu-primary';
		if ( genesis_superfish_enabled() )
			$class .= ' js-superfish';

		$args = array(
			'theme_location' => 'primary',
			'container'      => '',
			'menu'           => 'front-page-navigation', // !important! you need to give the name/slug of your menu
			'menu_class'     => $class,
			'echo'           => 0,
		);

		$nav = wp_nav_menu( $args );

		//* Do nothing if there is nothing to show
		if ( ! $nav )
			return;

		$nav_markup_open = genesis_markup( array(
			'html5'   => '<nav %s>',
			'xhtml'   => '<div id="nav">',
			'context' => 'nav-primary',
			'echo'    => false,
		) );
		$nav_markup_open .= genesis_structural_wrap( 'menu-primary', 'open', 0 );

		$nav_markup_close  = genesis_structural_wrap( 'menu-primary', 'close', 0 );
		$nav_markup_close .= genesis_html5() ? '</nav>' : '</div>';

		$nav_output = $nav_markup_open . $nav . $nav_markup_close;

		echo apply_filters( 'genesis_do_nav', $nav_output, $nav, $args );

	}
}