Just to confirm the fix for my machine:
Thanks to Jens' attachment in comment #2 (which I manually saved to on my machine as described), middle mouse button scrolling now works on my Dell Latitude E6500 running most current lucid (kernel 2.6.32-21-generic).
I: Bus=0011 Vendor=0002 Product=0008 Version=0000
N: Name="DualPoint Stick"
H: Handlers=mouse2 event12