Exchange 2003 Mailbox Recreation Problem

I am running Exchange 2003 SP2 and Outlook 2003 clients in a Windows Server 2003 environment.  In dealing with an oddly-behaving AD user's mailbox, I performed the following: used Exmerge to export this user's mailbox contents to a .PST file which I stored on a different server; deleted this user's exchange setup from their PC and Outlook client; from ADUC, I deleted this user's mailbox using Exchange Tasks, created a new mailbox (using the same alias) after it said this one was deleted, and then tried to reimport the .PST contents to this recreated mailbox using Exmerge again.  One thing I noticed when going through the import process, though, was that the directory name listed for this user in Exmerge now had 8 numbers attached to the end of the directory name (i.e. display name: john doe, directory name: jdoe12345678) and so the import failed due to the .PST file being jdoe.pst.  So, I exited Exmerge, changed the .PST file's name to jdoe12345678 and then was successfully able to import the contents into the mailbox.  The contents are there, but now we have NDRs to this user as I believe Exchange is thinking this user's email address is jdoe12345678 even though when I type jdoe in Outlook it appears to correctly resolve to John Doe before sending the message.  If I reply to a message from this user, the message gets through no problem, or if I send a new message from an outside account or an interface where Outlook doesn't autoresolve the address, it also gets through no problem.  I deleted the autocomplete entry from my Outlook that would pop up jdoe12345678, but it doesn't seem to help matters.  How can I correct this entry/mailbox?  I suppose it's probably going to involve deleting the account/mailbox again?  Sorry for rambling...