Back in the days, when i had weak arms, sometimes my biceps gave out while benchpressing cause they had to act as stabillizing antagonist for the triceps.....
Maybe that's why you can get some stimulation out of a pressing movement if you already have exhausted the biceps with specific movements, likewise you could do a set of chins at the end of your triceps workout to let the long head do some assistence, but i doubt that people with arms that are used to years of heavy eccentric scott curl and french presses, will get enough stimulation out of this, worth a try tough....