adding rounded block to other regions (Acquia Slate)

Howdy,

I would like to know if it's posible to add the rounded block (from eg sidebar_first) to other regions like content-wrapper ?

I tried adding it to template.php

// Add regions with rounded blocks (e.g., sidebar_first, sidebar_last) to $rounded_regions array
$rounded_regions = array(sidebar_first, content-wrapper);

But doesn't work.....do i need to add it somewhere else as well ?

Thanks so far!