You may also try this, but I guess it wont help, but it will not hurt. KB20418-"Add user from company directory" fails with the error, "The Specified user already exists in the available user list"
Quote KB Article:
"Add user from company directory" fails with the error, "The Specified user already exists in the available user list"
The message The specified user already exists in the available user list occurs when the BlackBerry Mail Store service has previously added the email address to the the user list of the BlackBerry Domain.
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The Add user from company directory is intended to be used when a new user has been created in Microsoft® Active Directory®, but the BlackBerry Mail Store service has not added the user the available user in the BlackBerry Domain. By default, the BlackBerry Mail Store service refreshes the user list every 24 hours. Alternatively, the administrator can manually refresh of the entire user list via BlackBerry Solution Topology > Component View > Email and selecting the Refresh the available user list from company directory option.
When an administrator receives this error, the user can be added by going to User > Create a user and entering in the user's email address.
I tried to post this in the other forum - the anti spam policy did not allow me to post the link. So I decided to put it here.