Although I am not capable to do this manouver yet... I was told how the manouver goes... and I am trying on the sim. If you start from left to right you come at a good speed, then pull to start the loop as you start rolling, as you go on, you need to trasfer form elevator to rudder, always trying to complete the loop. the trasfer has to be really smooth, is a matter of timming. I have done really nice only once on the sim. Just practice and good luck.

Hermann300