[Exim] needed "cased" $local_part_suffix

Hi All

I would like to support some sort of username-suffix or username+suffix to
deliver into maildir (in this case Courier-Imap) sub-folders directly.

I have the director set up and a transport almost set up. The problem is
that I'd like to support cased (ie, not caseless) suffixes. The username
delivery should be caseless as is default, but the suffix needs to be
mapped to the subfolders filename which is case dependent.

Is there any easy way or do I have to figure out some smartuser thing to
look it up caseless and turn locally_caseless to be false in the main
config? The problem with that is that I need to this to work for any of
the domains I serve but only for those that are resolved out of my LDAP
configuration (different set of directors and transports) than my passwd
file based accounts (in the same domains). I am in the process of
converting from a passwd file based system to an LDAP drive system so my
old users use mbox and virtual domain alias files I cooked up while the new
users use maildir and LDAP resolution (directory= comes from LDAP lookup
etc as well). Anyway, I don't want to have to go hack all my transports
and/or directors to do the right thing caseless and cased. I just want the
suffix, if it exists, to be "caseful" (or whatever the proper word is for
keeping its case).

Suggestions welcome
thanks
Chad