//This code goes in your functions.php file and will change "Quantity" to "Number of Bears" for the "code1" product

add_filter("foxyshop_quantity_title", "my_quantity_title");
function my_quantity_title($q) {
	global $product;
	if ($product['code'] == "code1") {
		return "Number of Bears";
	} else {
		return $q;
	}
}