Thank you very much for this answer. I tried the setting but without success. Anything else to do ?
I tried all setting but anyone seems to work ... It's very important for me because I paid a professionnal service (referencing) and have to customize descriptions and keywords for every product in the store (www.rosense-cosmetiques.fr). Now, without Joomsef, it's impossible to do that.
Every thing worked fine except the add to cart button !

Using paid Virtuemart extension, add to cart button don't work with Mynxx Rockettheme template.
When activating artio joomsef, nothing append : any prodduct added in cart ! Without Artio Joomsef, the add to cart button works fine. Impossible to find any solution ! Is there something to help me ?
Thank's in advance (sorry for my english ...)