question about wall climbing

hi ive been playing gunz for couple years now,but no matter what i try i can,t get my sword to slash out of my back if you know what i mean. this is used to climb walls with am i missing somthing here i tried everything i could it looks like the blade comes out from behind you when you do it any advice will be much appreciated.

You just have to have a quick finger movement and perhaps put your weapon switching to something more quicker to switch in between your gun and sword which is how you would make that view of you having your sword come out of your back.