No opacity on div inside a div with opacity

I have to use the asp.net ajax toolkit for a task and what I am doing is to display a div on the whole screen when an update progress control is triggered. The main div (that covers the whole screen) is having some opacity but when I try to have a div inside this one that one also gets some opacity even though I set it to none;

Example HTML:

<ProgressTemplate>
            <div class="updateProgressBox">
                <div class="updateProgressMessage">
                    <p>Processing request..</p>
                </div>
            </div>
</ProgressTemplate>

And CSS:

.updateProgressBox {
    top: 0px; 
    height: 100%; 
    background-color:Gray;
    opacity:0.7; 
    filter:alpha(opacity=70);
    vertical-align: middle; 
    left: 0px; 
    z-index: 999999; 
    width: 100%; 
    position: absolute;
    text-align: center;   
}

.updateProgressMessage {
    border: black 2px solid;
    background-color: #fff;
    z-index: 1000000;   
    padding: 20px;
    opacity:1.0; 
    filter:alpha(opacity=100);
    margin: 300px auto auto auto;
    font-weight: bold; 
    vertical-align: middle;
    width: 200px; 
    text-align: center
}

What should I do to make the div with the message have no transparency and white background color?