[exim] Delivering case sensitive...

Hi,

I'm trying to have exim deliver junk mails into a folder 'Junk' within
my cyrus server. I have the following code for this:

cyrus_spam:
driver = redirect
condition = "${if and{ {>{$spam_score_int}{60}} {bool{${lookup
mysql{QUERY_LUSER}}}} } }"
domains = +local_domains
data = ${lc:$local_part}+Junk
qualify_preserve_domain
redirect_router = cyrus_vdom

cyrus_vdom:
driver = accept
local_part_suffix = +*
local_part_suffix_optional
condition = "${if eq{} {${lookup mysql{QUERY_LUSER}}} {0}{1}}"
domains = +local_domains
transport = cyrus_ltcp
no_more

[...]

cyrus_ltcp:
driver = lmtp
rcpt_include_affixes
socket = /var/lib/imap/socket/lmtp
transport_filter = /usr/bin/tr -d \\000
delivery_date_add
envelope_to_add
return_path_add

The problem: When delivering, cyrus gets the local_part and the suffix
all lowercase. Instead of 'mailboxname+Junk' it's 'mailboxname+junk'.
And since mailfolders are case sensitive it's delivered to the Inbox
instead.

Any ideas, what I'm doing wrong?

Best, Jan.