request_var and $request->variable always return empty array

Given the post array:

$_POST['varname']['1'] = 'val1';
$_POST['varname']['2'] = 'val2';
$_POST['varname']['3'] = 'val3';

When trying to get the values out of the array $_POST['varname'] you can use either request_var('temp_ary', array()) (deprecated) or create an instance of the new $request class and use the $request->variable('varname', array());

In both cases an empty array is always returned.

If i use $request->variable('varname', array('1'=>'') the posted array is correctly returned.