[exim] Headers not being removed?

I must be doing something wrong here... I wanted a few headers removed before a message is processed and sent back out again on my mail server. After consulting this list, and the manual, I concluded I need to use the "headers_remove" feature. I enabled it for the remote_smtp transport (because I only want the headers removed when the message has an ultimate destination OFF my server), but they are still being sent in outgoing messages. Yes, I did restart exim after the config changes. ;-)

The relevant transport is as follows:

## transport/30_exim4-config_remote_smtp
#################################
# This transport is used for delivering messages over SMTP connections.

remote_smtp:
debug_print = "T: remote_smtp for $local_part@$domain"
driver = smtp
headers_remove = "X-FDA:X-Panda:X-Spam-Summary"
.ifdef REMOTE_SMTP_HOSTS_AVOID_TLS
hosts_avoid_tls = REMOTE_SMTP_HOSTS_AVOID_TLS
.endif
.ifdef REMOTE_SMTP_HEADERS_REWRITE
headers_rewrite = REMOTE_SMTP_HEADERS_REWRITE
.endif
.ifdef REMOTE_SMTP_RETURN_PATH
return_path = REMOTE_SMTP_RETURN_PATH
.endif
.ifdef REMOTE_SMTP_HELO_DATA
helo_data=REMOTE_SMTP_HELO_DATA
.endif
.ifdef DKIM_DOMAIN
dkim_domain = DKIM_DOMAIN
.endif
.ifdef DKIM_SELECTOR
dkim_selector = DKIM_SELECTOR
.endif
.ifdef DKIM_PRIVATE_KEY
dkim_private_key = DKIM_PRIVATE_KEY
.endif
.ifdef DKIM_CANON
dkim_canon = DKIM_CANON
.endif
.ifdef DKIM_STRICT
dkim_strict = DKIM_STRICT
.endif
.ifdef DKIM_SIGN_HEADERS
dkim_sign_headers = DKIM_SIGN_HEADERS
.endif
#####################################################
### end transport/30_exim4-config_remote_smtp

What have I done wrong?

thanks!
Bruce