Don't Worry. i made one myself. here is the code
Find
// The [calendar]!
if ($context['allow_calendar'])
echo '<li><a href="', $scripturl, '?action=calendar"><span>' , $txt['calendar24'] , '</span></a></li>';
Add after
// Start SMFShop Code
// The [shop] Button
echo '<li><a href="', $scripturl, '?action=shop"><span>Shop</span></a></li>';
// End SMFShop Code
You can add this to the Wiki