changing "no subject" to, well, a subject

[tree]

after an embarrassingly long time, i finally figured out how to turn on the option to display replacement text when there's no subject for an entry. however! i swear there used to be a field on the 'text' page in the customise area where you could put custom text to replace the standard "(no subject)". or maybe that was lj and we never had it here?

thanks to fu, i know how to make it disappear as if by magic, which would be my second choice. but ideally i would like to be able to have something visible that's not "no subject" when there's no subject. is there a magic for that? is there yet another ticky box i have resolutely failed to see over and over again?

thank you for halp.