I am unable to complete the maneuver as youdescribe with the Extra. If I give it full down elevator (stick forward) and full throttle it will stall and enter an inverted spin. Maybe it's not powerful enough (thrust/weight ratio of 1.5/1). It will work with the Depron 3D planes, they flip round again from the propwas over the tail.

The Extra isn't included with XTR, I downloaded it from rc-sim.de and I like it a lot more than the large models included with XTR.