Our BES infrastructure is managed in another country so have no view on their settings, etc..

The problem we encounter is:
If a user does simple delete of a mail in his Outlook client, the mail is also deleted on his BB.
When user does a shift-delete of a mail in his Outlook client, the mail is not deleted on his BB.

I raised this issue to the person in charge of the BES server, and he told me that this is normal behaviour. This sounds strange to me, so if soemeone here could confirm or I prefer deny this , thank you

Nobody could answer this ?

Found an answer.

Apparently the Blackberry when reconciliating, he looks the deleted items to know what to remove from the inbox.

As shift-delete an item, this item does not pass by the deleted items, the item is not removed from the Blackberry.

Also if you empty your deleted items before the reconcialiation , these items will not be removed from the Blackberry.