[Exim] first contact...

Hi!

I am a new french user of exim (so, excuse my poor english...).
Just two little questions (to begin):
1. I would like to use exim with user account especially created for it.
I us the command "useradd -g mail -p my pass -s /bin/false user1".
I would like no create the home directory (/home/user1) because it seem not
to be essential and i run 200 to 300 mail account on the server..
But exim don't recognize the new user (in the log it say that it didn't stat
the home directory...).
Is there a solution to correct this problem?...

2. I would like to propose my user to see mails with a webmail. This
solution need's an IMAP server.
Is it exim compatible?
Is there a specific solution for exim...

Thank's a lot and have a good day.

E.Bullier