You could try to
# mkdir /home/tmp
# mkdir /mnt/cf/tmp (you must\'ve done it already)
add to /etc/fstab:
/mnt/cf/tmp /home/tmp - bind 0 0
But if the card isn\'t mounted already, that could not work too... Maybe changing the script which mount the CF card, since you could need to take the CF out, and it could cause hangs if this dir isn\'t umounted...