@Sorcerer,
VoodooPS2Controller is not included with Clover and Rehabman's VoodooPS2Controller supports mainly Synaptics Touchpad, not Alps.
I have an E6420 running both versions 1.8.8 and 1.8.9 and no issue with KP. If your KP is related to VoodooPS2Controller v1.8.9, then try 1.8.8.
It's found in the E6420 bootpack here.