[Dovecot] Configuration Question.

Hi Everyone.

I have recently installed dovecot for the first time on a RHEL3
server. I have it working for the most part, but am a bit baffled by
part of the configuration, something that I am sure I am just doing
incorrectly.

I can successfully access my normal mailbox which is in /var/spool/ mail/username, but I also want to create mail folders, and that's the
problem I am having. I want the folders to live in

~/mail/

I have tried

default_mail_env = mbox:~/mail/:INBOX=/var/spool/mail/%u

and

default_mail_env = maildir:~/mail:INBOX=/var/spool/mail/%u

What on earth am I doing wrong? I'm sure it's something small that I
just don't understand.

Thanks James