Download doesn't have the Category fix, so this is how to fix it:
Find
Code:
$rowValue = $http_location ."/". $seo->_category_callback(array("home.php?cat=".$sitemap_category['categoryid'],false,'','categoryid='.$sitemap_category[''categoryid'],'',''), true, $sitemap_category['category']);
Change to:
Code:
$rowValue = $http_location ."/". $seo->_category_callback(array("home.php?cat=".$sitemap_category['categoryid'],false,'','cat='.$sitemap_category[''categoryid'],'',''), true, $sitemap_category['category']);
Notice that I changed one of categoryid to cat.
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On another note, the coding has a limit of 100 products
find the LIMIT 100 and remove it to let it have access to all your products.