Can't turn off hovering for Wacom Tablet Mouse

Question

I'm trying to use my Wacom Graphire2 on Ubuntu 12.04. However, when the mouse gets to the edge of the tablet pad, I have to lift it relatively high off the pad to "retake." I want it to become inactive when I lift it a little bit off the pad - like a normal mouse.

Browsing "xsetwacom --list parameters", it looks like I need to set CursorProximity lower. However when I run

xsetwacom --set "Wacom Graphire2 4x5 cursor" CursorProximity 10

It gives the error:

X Error of failed request:  BadValue (integer parameter out of range for operation)
  Major opcode of failed request:  144 (XInputExtension)
  Minor opcode of failed request:  37 (X_ChangeDeviceProperty)
  Value in failed request:  0x181
  Serial number of failed request:  18
  Current serial number in output stream:  21

I found another command that appears to change the same thing:

xinput set-prop "Wacom Graphire2 4x5 cursor" --type=int "Wacom Proximity Threshold" 10

But that gives the exact same error.

The default value is 42 for Graphire; 10 for Intuos. I'm trying to set my Graphire to 10. I tried setting it to 42 (it gives the same error).

I'm sure the device name is correct:

$ xsetwacom --list devices
Wacom Graphire2 4x5 stylus          id: 8   type: STYLUS 
Wacom Graphire2 4x5 eraser          id: 9   type: ERASER
Wacom Graphire2 4x5 cursor          id: 10  type: CURSOR

How do I disable this hovering behavior so my tablet mouse behaves like a real mouse?