Transparency of bar plots ?

Hi I am plotting transparent bars together with a curve (see please the attachment). I would like to have the curve located on top of the bars in such a way that bar under the curve is not visible. Unfortunately I am not able to get this done, the way it looks is always as if the curve is underneath the bars.

    h           = bar(x,mean(fg),1);
    set(h,'linestyle','none','ShowBaseline','off');
    alpha(get(h,'children'),.5);