CSS inverted round corners

[gerkintrigg]

I understand the round corner command in CSS and it works when I use it like this:

 

.round_corner_image{
-moz-border-radius: 15px;;
border-radius: 15px;
margin:2px;
}

 

My question is how to make a box like the logo here: http://ghostsinplymouth.co.uk/furniture/small_logo.jpg I want to make a box in CSS which has the same shape as the rusted metal and figured it's probably possible in CSS 3.

 

I've tried negative values but that doesn't work.

 

Any suggestions?

 

Thanks.

[Adam]

There is no CSS only solution, you need to use images.

[gerkintrigg]

Bummer.

Thanks.