[Exim] exim & maildirs

Hello there. I am trying to set up exim to deliver mail to maildirs;
specifically ~${local_part}. /home/${local_part} is not acceptable
because you can't assume where ~username is located. It can be
different for everyone.

Is there any way to do this? When I set up the "directory" line in
/usr/exim/configure, it complains if I have a ~ character.

Thanks,
Mark