I have a problem of gestion of stock

[jpcrea]

Hello
With the latest version of joomla 2.5 and virtuemart 2.0.24c, I have a problem of gestion of stock
I use storable variants, I put 2 items in stock. When I select 5 items it is ok " 5 x Item was added to your cart.
Reached max quantity, new quantity set to 2"
but when I make one item by one item, stock management does not work, I can buy over 100 items
Thanks by advance
JP