Messages disappear from BlackBerry after archived

We are starting to archive users in our system using the EmailXtender tool (version 4.81.655). We are new to this, with only a few "Pilot" users already archived. The most recent user who has been added is a BlackBerry user (not sure what our BES version or configuration is, but could find out if this is necessary). Archived messages appear to be deleted from the handheld device. However, when he goes to Outlook, the messages are still in the mailbox (Exchange 2003). Is this expected behavior?

We are archiving data over 90 days, and shortcutting only attachments. We were expecting that the email messages would have remained on the BB if they were archived, but the user would have problems accessing attachments that went through the shortcut process. However it looks like the archive process did something to remove the messages from the device.