To add the support is enough to just change two files in kernel source:
ftdi_sio.h
ftdi_sio.c
In the first one add:
#define WBE_VID 0×104F
#define WBE_SMARTMOUSE_PID 0×0002 /* Smartmouse USB -Maciek*/
In the second:
{ USB_DEVICE(WBE_VID, WBE_SMARTMOUSE_PID) },