keyboard – lxde inverted mouse scroll

I Just installed l-ubuntu, and installed LXDE on it. First of all I really love the LXDE due to its high performance. But what I don’t liked that I am not able to do the natural mouse scrolling (inverted scrolling).

Can someone help me out
I used this line in my shell : echo "pointer = 1 2 3 5 4 7 6 8 9 10 11 12" > ~/.Xmodmap && xmodmap .Xmodmap
But it’s actually not working for me
Any other solution?