i have found a solution!
i'm gonna try to explain how i find the solution....
first i'd like to apologyse , cause my english is not very good (i'm french)
from default there are only 4 SATA connexion.
so i activate AHCI driver to earn 2 more SATA connexion
i have plug the vélociraptor on one of this 2 more connexion.
and it doesn't work.
when i try to plug the HD on one of the 4 primary connexion, it finaly works!
as always, it was so simple...at the end....