Okay... I have finally figured out how to do this...
What you need to do is:
1) When the mission starts, deactivate Option 1 2) Restart from Checkpoint 3) Hit the LH and check his HP go down 4) Activate Option 1, and kill the LH...
Have fun!!
*Edit* You may have to disable all the trainer options you have on in order for this to work...
its very easy to beat leader hunter with claws in the 3rd stage all u have to do is run to away from it and when at suitable distance from it juss attack with ground spike and then quiqly change ur position either by sprinting or gliding remember quality of coupling airdash with gliding really matters while escaping from any action