The world's largest retailer, Wal-Mart Inc, on Monday said September sales are back on track after a disappointing August and it expects same-store sales to rise up to six per cent this month. The Arkansas-based company, which posted a 3.8 per cent climb in same-store sales last month, added it also sees stronger same-store sales at its Sam's Club division which reported a 1.1 per cent rise in August.