How to scroll using an external USB trackpad that is not a magic-mouse?
I suspect that the trackpad settings/bluetooth settings may not be all that useful for this.
Firstly if you do a system report (Apple icon ► About This Mac ► System Report...), you can check to see if the USB device is recognised. This seems to be the case since your saying it recognises left and right clicks.
My only suggestion is that this may require some third party software to properly recognise it. For example: SteerMouse. Similar to if you have ever installed a joy stick for a simulator, it usually requires the actual third party software to recognise it.