[exim] not syslogging correctly

I have exim set to use syslog, and I set SYSLOG_LONG_LINES=yes at
buildtime. I'm using syslog-ng, and have set log_msg_size(8192) in it. I
have successfully sent 3k test lines to it. Exim however truncates the log
line at around 1000 bytes. (having set SYSLOG_LONG_LINES=yes it does not
do the [1/3] log line splitting, so it does somewhat honor the option).
The rest of the log line does not appear elsewhere in any log file, it's
just gone..

Any ideas?

-Mike