Thank you to both of you. I never thought of that, but have adapted it to do what I want it to:
#!/bin/sh test -d IMAPdir || mkdir IMAPdir && ln -s ../Maildir IMAPdir/INBOX exec $@ did the trick. I'm keeping with the conventional vpopmail setup, and making the link for the IMAP service. umask is already 077, so all the permissions are correct. Thanks for everyone's help. -M
