As having same problem I searched a bit around but was not able to find a solution. The product feed (/index.php?rss=true&action=product_list) cannot seen in case there are special characters like german umlaute as well as stuff like ’. Products etc are shown nice in the web, only the feed doesn’t work. I guess the prob starts in file wp-shopping-cart.old.php from line 1111 onwards but have no idea how to solve it 🙁 Any idea highly welcome 🙂
