My personal opinion is that if you have no other choice but to try and out climb it, and you are going down, use what ever attitude will give you the better RoC.
This makes as much sense to me as experimenting with different airspeeds in an engine failure coz you'd have to be completely anal to do what you have been taught and practiced in a REAL failure!
Sparky's 10 commandments (
http://www.mountainflying.com/Errata...t%20Pocket.pdf) Say that if terrain is a problem you should not put yourself in the situation where the difference is vital. If you start going down turn away.
Elsewhere it says:
If you encounter unexpected downdrafts, diving–away from the visualized downdraft–to maintain airspeed will generally lessen the total displacement effect of the downdraft (altitude loss). Although the rate of descent is greater at the higher airspeed, you will be under the influence of the sink for a shorter period of time.
(as CFICARE suggests).
So to answer your question I would suggest that:
Don't put yourself in the situation near terrain, or leave an escape route OTHER than climbing through it.
If you ignored Sparky and there is a hill in front BAOC.
If there is nothing in the way except an unwanted trend of down-ness, do whatever.
'Course this is just stuff I googled, I have no mountain flying qualifications to spruik here...