try these steps:

on the blackberry itself go into messages, wheel-click, goto Options > EMail Reconciliation > check to ensure Wireless reconcile is on, if not, change it.

On the BES, keep in mind this is 4.0 I've used, double-click the users name, on the screen that comes up, click on PIM Sync on the left, and at the top there is an option for Wireless Reconcile True/False, obviously that needs to be True, a few lines down there is a Messages Settings section, make sure syncronization is set to true, type is bi-directional as well.

Also I've been told that the ACL of the users mailbox has to have the correct settings, we've got ours so the BB server is part of the LocalDomainServer/Admin groups, here's what we've got it as:

These are in the ACL of the mailbox with the following settings:

LocalDomainAdmin - Mixed group, manager access
LocalDomainServers - Server group, manager access
OtherDomainServers - unspecified, no access

We stopped doing the desktop sync since going to 4.0 bes and it's all wireless, so on the handheld itself, under messages > options > email reconciliation we've got it set to Desktop client (as opposed to web client), handheld and mailbox (have to be careful with this, if they delete from BB, it deletes from their mailbox), reconcile on, and on conflicts mailbox wins.


let me know if that works or not.