sed replacing character in a file

I need to replace a single character in a/etc/request-key.conf

The file format is;

###############################################################################
#
# Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
# Written by David Howells (dhowells@redhat.com)
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version
# 2 of the License, or (at your option) any later version.
#
###############################################################################


###############################################################################
#
# We can run programs or scripts
# - Macro substitutions in arguments:
#   %%...   %...
#   %o  operation name
#   %k  ID of key being operated upon
#   %t  type of key being operated upon
#   %d  description of key being operated upon
#   %c  callout info
#   %u  UID of requestor
#   %g  GID of requestor
#   %T  thread keyring of requestor (may be 0)
#   %P  process keyring of requestor (may be 0)
#   %S  session keyring of requestor (may be the user's default session)
#
################################################################################

#OP TYPE    DESCRIPTION CALLOUT INFO    PROGRAM ARG1 ARG2 ARG3 ...
#====== ======= =============== =============== ===============================
create  dns_resolver *      *               /sbin/key.dns_resolver %k
create  user    debug:*     negate      /bin/keyctl negate %k 30 %S
create  user    debug:*         rejected        /bin/keyctl reject %k 30 %c %S
create  user    debug:*         expired         /bin/keyctl reject %k 30 %c %S
create  user    debug:*         revoked         /bin/keyctl reject %k 30 %c %S
create  user    debug:loop:*    *       |/bin/cat
create  user    debug:*     *       /usr/share/keyutils/request-key-debug.sh %k %d %c %S
create  cifs.spnego *   *       /usr/sbin/cifs.upcall -c %k
create  dns_resolver    *   *       /usr/sbin/cifs.upcall %k
negate  *   *       *       /bin/keyctl negate %k 30 %S

So I need the 3rd last line to go from;

create cifs.spnego * * /usr/sbin/cifs.upcall -c %k

to;

create cifs.spnego * * /usr/sbin/cifs.upcall -t %k

I have tried;

sed -i 's/^\(create cifs.spnego *cifs.upcall\) \(%k\)/\1 -t \2/' /etc/request-key.conf

Bu treally I just need to replace the -c with a -t