When u press crouch + back + attack....that performs a 2 handed BS .... This move is different because...as the name suggests... the player uses 2 hands when bs'ing instead of 1..... try it out if you dont know it!
2 Hand BS is way more powerful then normal.
The problem began because you weren't more specific.
As I pointed out "2handbs" could be anything...
I'll try what you suggested (you didn't say what saber type it was used with, but I'll try them all)... and see what happens.