Apparently, after doing more research, "You may not obtain the deletion or expungement of a record related to a case that resulted in a conviction or other disposition adverse to you. Examples of dispositions that are adverse to you include the entry of an order to dismiss entered after the successful completion of a period of probation, suspension, or deferral of sentence.."
From Aaron's quote at this thread:
http://www.expertlaw.com/forums/showthread.php?t=24188

