function customscrollup(elem)
{
    var UL = $(elem).parent();
    var elem_height = $(UL).find('LI:eq(0)').height();
    var mtop = Math.abs(delpx($(UL).find('LI:eq(0)').css('margin-top')));
    
    if(mtop > 0)
    {
        mtop = mtop - elem_height;
        if(mtop < 0) mtop = 0;
        $(UL).find('LI:eq(0)').animate({ marginTop: '-'+mtop+'px' }, 200);
    }
    return false;
}

function customscrolldown(elem)
{
    var UL = $(elem).parent();
    var elem_height = $(UL).find('LI:eq(0)').height();
    var elems_count = $(UL).find('LI').length;
    var mtop = Math.abs(delpx($(UL).find('LI:eq(0)').css('margin-top')));
    
    var max = (elem_height * elems_count) - $(UL).parent().height();
    
    if(mtop <= max)
    {
        mtop = mtop + elem_height;
        $(UL).find('LI:eq(0)').animate({ marginTop: '-'+mtop+'px' }, 200);
    }
    return false;
}

function delpx($string)
{
	var $temp = new String;
	$temp = $string;
	$tmp = $temp.replace(/\px/g, '');
	return $tmp;
}