[Exim] LDAP lookup query in address rewrite

Hello,

I'm investigating (only investigating remember) the ability of using a LDAP
lookup to create an "outgoing" change of $local_part. This will enable us to
send e-mail out from the University that hit Exim as "fbloggs@???"
and leave as "fred.bloggs@???".

I include below what I've been testing but I'm only getting failures such
as:

2003-08-07 14:40:09 Exim configuration error in line 463:
unknown rewrite flag character 'e' (could be missing quotes round
replacement item)

The lookup is of the form:

*@glam.ac.uk ${lookup ldap {ldap:///....?displayName?sub?\

(saMAccountName=$local_part)}}{$value}fail}@??? Ffr

I know this needs to be "quoted" but I'm not sure where they need to sit or
indeed
if the whole thing is permissible.

Hope you can help.

best regards
Martyn