Cheers,
Where can I find information in the backend regarding the best sales products ?
You can use the module named VirtueMart Products to display the best sales product on your website. This module is installed with "com_virtuemart_ext_aio" package.
I've installed the module,it shows the best sales in the front page.
The problem is that I can't see in the Virtue Mart component information regarding the products that have been best saled. There must be a way to also know this information in the administration area.
The module will display the product(s) which have the highest number of sales. This is not shown in the BE, although can be worked out from the orders list. You can use an external order handling program to extract the information. Or maybe use/modify a VM extension, eg http://forum.virtuemart.net/index.php?topic=107737.0