A new interface for managing sideboxes in the admin is in development for v1.4.

In the meantime, you *should* use the admin interface for making your edits. If you are database-savvy, and have studied the database structure and are sure you know what you're doing and understand what changes affect what results and are dependent on what other settings, you can edit your sidebox details by directly editing the raw database settings in the "layout_boxes" table in the database.