OK EVERYONE! I just got off the phone with Spencer @ RIM and we found the problem! The documentation is wrong... The documentation on PAGE 27 of BlackBerry Enterprise Server for Microsoft Exchange - Version 4.1.4 STATES:

3.Type the following command:
set-mailboxserver xxx8220;<messaging_server_name>xxx8221; | add-adpermission xxx8211;user xxx8220;BESAdminxxx8221;
xxx8211;accessrights ExtendedRight xxx8211;extendedrights Send-As, Receive-As, ms-Exch-Store-Admin

IT NEEDS TO BE:

set-mailboxserver xxx8220;<messaging_server_name>xxx8221; | add-adpermission xxx8211;user xxx8220;BESAdminxxx8221;
xxx8211;accessrights GenericRead, GenericWrite, ExtendedRight xxx8211;extendedrights Send-As, Receive-As, ms-Exch-Store-Admin

Notice the addition of GenericRead and GenericWrite.

This will resolve all one-way synchronization issues with Calendar! You dont even need to restart the darn BES services, it just starts working...

RIM is changing the installation doucmentation ASAP...

Once again! Thanks Spencer @ RIM! Appreciate all the time today to resolve this issue.

Additional information: KB12483 from RIM has the correct permission statements to isssue. Follow the link here: BlackBerry Search Results

Bradley

Awesome to hear that you got it fixed. I've been searching for a few days and haven't been able to resolve it. I followed your steps and still have the one way sync. Would you mind posting your:

get-mailboxserver <server_name> | get-ADpermission -user <service_account_name> | FL

Of course with the appropriate edits I'd like to compare mine to yours.