Problem with "-" char in user mail address

Hi 2 all,

I have prob while adding new user with "-" char in mail address. User 
are created in mysql user table but maildir isnt created. When I manualy 
create maildir, imap and pop is working. I can send message but and I 
cant recieve any and I get  "Unknown user"  error in exim log.
Does anyone have this type of problem and what is solution for it.
Thanx a lot
Bane