First, archiving in shared folders is dependent upon the archive setting of the shared folder's "owner".
If you are set with "manual/delete" and archive, then messages will stay in the folder unless they are deleted or your system is set up to auto delete after a certain length of time.
If you are set with "auto" archive, then messages should go to a folder in the "owners" archive which now makes it tough for other users of the shared folder to access these messages. Novell defintely needs to do something about this in future GroupWise upgrades instead of having users purchase "add ons".
Although we don't use Nexic Personal Publisher, I would look into this if users of shared folders need access to older messages.
Regards,
Stars