aarrgg...move keeps eluding me!

Ok i keep trying but i can't figure it out...Lei Fei has punch where he leaps forward and makes what looks like a mid punch and it covers a good distance. I've done it by accident but i can't quite seem to get the hang of it. I think its close to back-forward+P+K but i am missing something... can it only be done from a specific stance?

 

P+K from Scorpion stance (d+P+K+G)

 

Many thanks!

This grasshopper will now go practice some more...