Win32::GUI::SendMessage($hwnd, HDM_SETITEM, $columnClicked, $hditem_ptr);
Win32::GUI::SendMessage($hwnd, HDM_SETITEM, $columnClicked, unpack('L!', $hditem_ptr));

$sendMessage = new Win32::API("user32","SendMessage","NNIP","I");
$sendMessage->Call($hwnd, HDM_SETITEM, $columnClicked, $hditem_ptr);
$sendMessage->Call($hwnd, HDM_SETITEM, $columnClicked, unpack('L!', $hditem_ptr));

$listview->Show(1); # refresh