How to play NFS Rivals with PS2 gamepad + adapter ps2 to usb

I just installed the game and I have trouble activating my ps2 controller.
Thank you for helping me.

NB: I installed the game in program files (64)

Gamepad: http://upload.wikimedia.org/wikipedia/commons/thumb/a/af/PS2_Dualshock2_Controller.jpg/749px-PS2_Dualshock2_Controller.jpg

Adapter: http://i00.i.aliimg.com/wsphoto/v0/629492636/8pcs-2-Port-Dual-font-b-USB-b-font-Game-Converter-Adapter-for-Sony-font-b.jpg