[Exim] LDAP query

just a dummy question.
I have a problem with the syntax of the LDAP queries with USER and PASS
options.

I tried something like :

search_type = ldap
query = "user='cn=........' pass=****** ldap:///..... "

but it doesn't work.
I tried a lot of combinations of syntax with " and ' and { but i didn't
found

does someone know the right syntax
thank you

yann Algayon