I agree with Captain Pit Bull 100%
If you cannot follow the TCAS demands, what is the point in knowing about it? You can maneouvre visually if you get a TA in that case! Your TCAS TA/RA also lets the other aircraft know that your system is operational. Telling it porkies can only DEGRADE safety. Our QRH (B757)also states in an engine out case;
TRANSPONDER MODE SELECTOR............TA
[Prevents climb commands which can exceed single engine performance capability.]
In my opinion it is a stupid idea to set it to TA/RA with an engine out! Well... At least you will know what you SHOULD have done, as you smash into the side of an other aircraft in a busy TMA!!
Hope to God it aint mine!!!!
But hey thats my opinion, and what do I know??
Safe flying.
Eff Oh.