Changing elgg date format

Where is the date format defined in elgg? I don't want to use July 28, 2012  , but something like 28.07.2012. On views/default/output there's a file containing:

if ($vars['value'] > 86400) {
    echo date("F j, Y",$vars['value']);
}

But when I change it, nothing happens... Oh: I user elgg 1.7.7