function setupMouseOver(id,dest_id) {
	var el = $('btn_'+id);
	el.setStyle('opacity',0.01);
	
	var NavFx = new Fx.Tween(el, {duration:300, transition:Fx.Transitions.Quart.easeInOut});
	el.addEvent('mouseleave', function() { NavFx.pause(); NavFx.start('opacity', 1, 0.01) } ); //NavFx.start(1, 0.01);
	el.addEvent('mouseenter', function() { NavFx.pause(); NavFx.start('opacity', 0.01, 1) }); //NavFx.start(0.01, 1); 	

	el.setStyle('cursor','pointer');	
}

function selectNavItem(id) {
	var el = $('btn_'+id);
	el.removeEvents();
	el.setStyle('opacity',1);
	el.setProperty('src','/images/menu_btn_'+id+'_on.jpg');
	el.setStyle('cursor','default');
}