All right,
I've updated my BES Server and installed the MR2.
It's now a little better since the setting :
Wireless Message Reconciliation is Enabled. (on the BES)
I did a cable activation, the activation went throught without any error.
the wireless email reconciliation is enabled too on the blackberry device. (under Messages > Options > Email Reconciliation > Wireless Reconcile)
Everything looks good on the paper eept that I can't receive or send email from the BB device.
I tried to send again the addresse book and policy but both don't work.
I'm going to leave the issue like that for now because I've other things to deal with and it's already 4 pm in France.
Thanks for your help Penguin,
I'll post the answer when I'll find it.
Good weekend