[exim] mysql config

I'm sorry if this is a FAQ. I tried looking in the archives and found
nothing.

I'm trying to setup exim to read a mysql database to identify users and
their maildirs. I used an example from the internet but apparently it's for
too old a version of exim or something because it says the router should
use the aliasfile driver,but exim says it can't find an aliasfile driver.

Any good tips on configuring Exim to read it's user info from a mysql table
and to ensure it does SMTP auth correctly against that table is appreciated.

Thanks!