I have an Acer Aspire 1640z that had the same problem. All I did was install the new drivers at http://www.synaptics.com/support/drive.cfm
I didnt do any extra steps and all works fine for me (even side scrolling).
Under Controls Panel/Mouse/Hardware/Properties/Advanced Settings I have:
Sample Rate: 100
Wheel Detection: Assume Wheel is present
Input Buffer Length: 100
Fast initializtion is checked.
I did turn off coasting in the Synaptics settings, I dont like it. Its under Virtual Scrolling-Long Distance Scrolling.