[jQuery] Apply alpha filter via css dynamically not working IE7

[kevinm]

I am trying to apply this

.applyOpacity {
        background: #fff;
        filter:alpha(opacity=50);
        -moz-opacity:0.50;
        -khtml-opacity: 0.50;
        opacity: 0.50;
}

To an existing DIV dynamically via a hover and in IE7 this fails. Is
that correct? should I do this differently?

this is function

$("#talentThumb li a").hover(function(e) {
                $(this).parent().addClass('hoverSlide');
                $('#talentThumb li a').addClass('applyOpacity');
                $(this).toggleClass('applyOpacity');
        }, function() {
                $(this).parent().removeClass('hoverSlide');
                $('#talentThumb li a').removeClass('applyOpacity');
        });

Thanks