floating a div into the vertical space above - ie7 issue

You can see my issue here - http://jsfiddle.net/WuWPs/5/

Essentially I'm trying to have the lower three divs move up to below the first div.

I'm having no problems achieving this in a modern browser, but with ie7 it looks a mess.

I can't edit the html, I'd like to achieve the effect with only css changes.

I did it by only changing the CSS, as requested.

See: http://jsfiddle.net/thirtydot/fVzDT/

In fact, your CSS hasn't actually been changed, I've simply added some magic at the end that is applied in only IE7:

/* ie7 hack */
*+html .block1, *+html .block2 {
    float: none;
    vertical-align: top;
    display: inline;
    zoom: 1
}