Hi John,
Thanks for you Help,
In fact i have find a solution, maybe it could be help someone,
In configuration of virtuemart in "Order Products" choose "Order" for the both parameters,
After in your module caroussel choose random, you can put a echo $product->ordering in line 130 of default.php of caroussel module to show the ordering for each product.
If you have for example 80 total products and 4 products by slide you wil see 66,67,68,69 ordering in first slide and 62,63,64,65 in the second slide,
So apply an array_reverse($products) to have the ordering ASC on default.php
After that change float left to float right on #FlexibleCarouselHorizontal .FlexibleCarousel-contents-horizontal > div > div on line 141,
I hope it could help someone :)
See you and thanks for your support John !
B.