Two or three days ago I tried this also! It didn’t work for me either! It looks like our only choices are these:
[root@ipfire etc] # ls -al /etc/fc*
-rw-r----- 1 root cron 5 Feb 7 06:58 /etc/fcron.allow
-rw-r----- 1 root cron 670 Mar 11 22:04 /etc/fcron.conf
-rw-r----- 1 root cron 4 Feb 7 06:58 /etc/fcron.deny
/etc/fcron.cyclic:
total 12
drwxr-xr-x 2 root root 4096 Feb 7 08:48 .
drwxr-xr-x 54 root root 4096 Jun 12 03:51 ..
-rw-r--r-- 1 root root 34 Feb 7 06:58 info.txt
/etc/fcron.daily:
total 24
drwxr-xr-x 2 root root 4096 Apr 26 08:46 .
drwxr-xr-x 54 root root 4096 Jun 12 03:51 ..
-rw-r--r-- 1 root root 33 Feb 7 06:58 info.txt
...
/etc/fcron.hourly:
total 12
drwxr-xr-x 2 root root 4096 Mar 9 13:48 .
drwxr-xr-x 54 root root 4096 Jun 12 03:51 ..
-rw-r--r-- 1 root root 34 Feb 7 06:58 info.txt
...
/etc/fcron.minutely:
total 12
drwxr-xr-x 2 root root 4096 Feb 7 08:48 .
drwxr-xr-x 54 root root 4096 Jun 12 03:51 ..
-rw-r--r-- 1 root root 36 Feb 7 06:58 info.txt
/etc/fcron.monthly:
total 12
drwxr-xr-x 2 root root 4096 Apr 24 20:16 .
drwxr-xr-x 54 root root 4096 Jun 12 03:51 ..
-rw-r--r-- 1 root root 35 Feb 7 06:58 info.txt
/etc/fcron.weekly:
total 16
drwxr-xr-x 2 root root 4096 Apr 24 20:42 .
drwxr-xr-x 54 root root 4096 Jun 12 03:51 ..
-rw-r--r-- 1 root root 34 Feb 7 06:58 info.txt
...